101 faits aléatoires pour nourrir votre cerveau

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Transcript

00:00:00The teeth of the squirrels never stop growing, but the animals use them by eating nuts and other hard foods.

00:00:06The front of the teeth of the rodents is actually orange.

00:00:09It's because they are covered with a special and resistant mesh.

00:00:12I bet you're glad you don't have to deal with that.

00:00:15Some species of birds are not afraid of biting strong peppers.

00:00:19It's because they can't feel the spiciness.

00:00:22Peppers burn your mouth because they contain a special chemical product, capsaicin.

00:00:27But birds don't have the necessary taste buds to feel the effects.

00:00:31The horn of the rhinoceros is made of hair, or at least the same protein as the one that makes up your hair and nails.

00:00:38This protein is called keratin.

00:00:41Such a horn is quite unique, since other animals have horns with a bone center.

00:00:46The woodpecker can peck wood 20 times per second.

00:00:49This rate is almost too high for the human eye to notice it.

00:00:53How much wood would a woodpecker peck if a woodpecker could peck wood?

00:00:57The number of woodpeckers often reaches a total of 8,000 to 12,000 per day.

00:01:02The starfish has eyes.

00:01:04One at the end of each of its arms.

00:01:06Its eyes are groups of light-sensitive cells.

00:01:10Frogs don't need to drink water.

00:01:12It's their skin that allows them to hydrate by absorbing water, while providing them with the oxygen they need to breathe.

00:01:19This could save time.

00:01:21Most caterpillars have about 4,000 muscles in their body, and nearly 250 of them are in the head alone.

00:01:28Christmas tree branches are much more beautiful than you can imagine.

00:01:33But even if these little trees look great,

00:01:36two-thirds of the body of the worm is hidden in a tube of calcium carbonate.

00:01:40And what's the point?

00:01:42Well, to be honest, I don't know.

00:01:44The famous rhinoceros' teeth are actually their teeth that are, in a way, twisted.

00:01:49These sea unicorns only have two teeth.

00:01:51In males, one of them goes through the upper lip.

00:01:54Unlike your teeth, this one is hard on the inside, and sensitive and tender on the outside.

00:02:00Ants don't have teeth, but that's not a problem.

00:02:04This creature has a super long tongue.

00:02:07This tongue allows the animal to lick more than 35,000 termites and ants a day.

00:02:12It's one way or another to appease hunger.

00:02:15The worm can jump more than 200 times the length of its body.

00:02:19If humans had this ability, they would jump as high as the Empire State Building.

00:02:25The eggs of the reindeer with red eyes can hatch earlier if they feel that their environment is not safe.

00:02:31Small animals with rapid metabolism see in slow motion.

00:02:35This helps them escape larger creatures.

00:02:38Koalas' fingerprints are very, very similar to that of humans.

00:02:43Sometimes the fingerprints of these animals are even confused with ours on crime scenes.

00:02:48Probably just in Australia.

00:02:50The sweat of the hippopotamus is pink, and it's not really sweat.

00:02:54It's an oily, reddish liquid.

00:02:56Its function is not to cool the body, but to moisturize the skin and protect it.

00:03:00This fluid also works as an antibiotic.

00:03:03So if you have a sunburn or a cut, you can get hippopotamus ointment.

00:03:08The skin of polar bears is black, and the fur of their fur is hollow and almost transparent.

00:03:14These animals have fur that grows even on the lower part of their legs.

00:03:18This gives them a better grip on the ice and protects them from the cold.

00:03:22Some species of tarantula, among the largest spiders in the world, can live without food for more than two years.

00:03:29I always find them scary.

00:03:32Ornithorhynchus close their eyes when they kiss.

00:03:35I mean, when they swim.

00:03:37They have special skin folds that cover their ears and eyes.

00:03:40They prevent water from entering inside.

00:03:43The nostrils of these animals are also waterproof.

00:03:46Mammals can't walk backwards.

00:03:48But scientists don't know why.

00:03:50These birds that don't fly are the only ones with calf muscles.

00:03:53Mammals can sprint very quickly.

00:03:56They can also walk long distances.

00:03:58But they can't walk backwards.

00:04:01Crocodiles can't move their tongue because it's attached to the palate of their mouth.

00:04:06It keeps the throat closed and protects the animal's respiratory tract.

00:04:10Water snakes, dolphins, whales, alligators, crocodiles and turtles can drown.

00:04:17This happens if they stay submerged for too long.

00:04:20These animals can't breathe in the water.

00:04:22They can only hold their breath for a very long time.

00:04:25Only one species of bird can fly backwards.

00:04:27It's the hummingbirds.

00:04:29So go talk to the seagulls.

00:04:31These little birds can also flap their wings up to 80 times per second.

00:04:35Despite the appearance of hummingbirds,

00:04:37these little animals are more closely related to elephants than to hummingbirds.

00:04:41Maybe that's why they have such a nasal appendix.

00:04:45Hummingbirds and elephants use it to nibble on insects.

00:04:49Cats, as well as other felines, can't taste sweet foods.

00:04:53They don't have the necessary taste buds for that.

00:04:56Too bad, it does more for me.

00:04:58Pink flames can only eat with their head down.

00:05:02That's why the lower part of their beak is massive,

00:05:05while the upper part is mobile.

00:05:07Such a device is perfect for feeding the head down.

00:05:11But it's the opposite of what other birds have.

00:05:14It's not easy to be pink.

00:05:16The tiger's skin is as striped as their fur.

00:05:19That's all I have to say about that.

00:05:21When the toucans sleep, they curl up into pretty tight balls.

00:05:26These birds turn their heads so that their tails cover their heads

00:05:29and the beak rests on the back.

00:05:31So yes, they curl up into balls.

00:05:33The ostrich has the largest eyes in the animal kingdom.

00:05:36They are more massive than the bird's brain.

00:05:39Each eye is as big as a billiard ball.

00:05:42That's why clown fish are born sick.

00:05:45But in some circumstances, they can turn into females.

00:05:48This change is irreversible.

00:05:51Unlike most fish, when hippos mate, they do it for life.

00:05:56Even cuter, when partners travel, they move side by side

00:05:59and often hang on to each other's tails.

00:06:02The male usually ends up carrying the luggage.

00:06:05Termites never sleep.

00:06:07They don't need to recharge their batteries.

00:06:09But they can eat 24 hours a day, 7 days a week.

00:06:12And they eat at home.

00:06:14The lazy one needs up to 2 weeks to digest its food.

00:06:18Hey, take your time. No rush.

00:06:21There's nothing on the schedule.

00:06:23Dog's nasal imprints can be used for their identification.

00:06:27They are similar to human fingerprints and unique to each animal.

00:06:31Hippos don't have eye globes.

00:06:33Instead, they have eye tubes that don't move in their orbits.

00:06:37Penguins don't have external ears.

00:06:40But their ears are exceptionally thin,

00:06:42especially when they are in the presence of polar bears.

00:06:45Jellyfish are 98% water-based.

00:06:48That's why when they are thrown onto the shore,

00:06:51their bodies can evaporate in the air after just a few hours.

00:06:55And if a bottle-up occurs underwater,

00:06:57an alligator will always find a place for a lamb.

00:07:00There you have it.

00:07:02Grizzlies have such a powerful bite

00:07:05that they can crush a bowling ball.

00:07:08So it's better to let them win.

00:07:10Giant pandas are not complicated when it comes to where they sleep.

00:07:14They usually sleep where they are.

00:07:17In most cases, on the ground of the forest.

00:07:20The giant panda's newborns are tiny.

00:07:23They weigh as much as a small cup of coffee

00:07:25and are smaller than a mouse.

00:07:27The red-handed fish can walk on the bottom of the ocean

00:07:30with the help of its sticks.

00:07:32But of course, they are not really hands,

00:07:34but evolved fins.

00:07:36Really.

00:07:37Cats are not used to petting each other.

00:07:39A study has shown that felines use this mode of communication

00:07:43especially to attract our attention, us humans.

00:07:46And it works.

00:07:48Lazy people can't whine.

00:07:50It's not because they are too busy digesting their two-week old meal.

00:07:54Their fur is sometimes covered with algae.

00:07:57And when they are too hot or too cold,

00:07:59their metabolism stops.

00:08:01During difficult periods,

00:08:02the immortal jellyfish transform

00:08:04to regain the state of their early youth.

00:08:07Once they have reached the stage

00:08:09where they are just a pile of soft tissue,

00:08:11a bit like me,

00:08:12these creatures begin to grow.

00:08:14And this process can apparently be repeated over and over again.

00:08:18The closest living relatives of the T-Rex

00:08:20are chickens and ostriches.

00:08:22Don't turn around!

00:08:24The muren has another series of jaws

00:08:26that can come out of its throat.

00:08:28First, the main jaws close

00:08:30around an unlucky marine creature.

00:08:32Then, the additional jaw

00:08:34grabs the future meal of the eel

00:08:36with its teeth pointing backwards

00:08:38and slicing like razors.

00:08:40And after that, the captured animal

00:08:42is brought back to the muren's throat.

00:08:44I just lost my appetite.

00:08:46Some species of snails have a hairy shell.

00:08:49Thanks to these hairs,

00:08:50snails can better adhere to wet surfaces.

00:08:53When the jellyfish hunt,

00:08:55they often gather in groups

00:08:57and apply a tactic of netting to bubbles

00:08:59to catch their food.

00:09:01Bubbles do not let the fishing lines escape.

00:09:04Snow leopards cannot roar

00:09:06like other large felines.

00:09:08This is due to their less developed vocal cords.

00:09:11But these animals can howl,

00:09:13growl, whistle and even purr.

00:09:15To stay away from their group

00:09:17during nap time,

00:09:19sea otters hold each other by the hand.

00:09:21They can also pounce

00:09:23on giant eels with the same goal.

00:09:25Lions are often called

00:09:27the kings of the savannah.

00:09:29And I thought it was the king of the jungle.

00:09:31And yet, up to 90% of the hunting

00:09:33in the troop is carried out by females.

00:09:36Eels are in charge of protecting

00:09:38the territory and the members of the troop.

00:09:40And they make a delicious potato salad

00:09:42known as...

00:09:44Hakuna Matata!

00:09:46Cats are famous

00:09:48for their amazing ability

00:09:50to move their ears.

00:09:52All because kittens have 32 muscles

00:09:54in each external ear.

00:09:56Some species of sharks

00:09:58can shine in the dark.

00:10:00Unfortunately, only other sharks

00:10:02can see this greenish glow.

00:10:04You have up to 8,000 taste buds,

00:10:06but your dog only has a little over 1,500.

00:10:08The blue jay can imitate other birds.

00:10:11The blue jay uses it to make other birds

00:10:13flee from its territory.

00:10:15The slow lorries are incredibly cute

00:10:17and just as perfidious.

00:10:19They are the only venomous primates known.

00:10:21They have a gland in the hollow of their arms.

00:10:23They secrete toxins that can have

00:10:25very unpleasant consequences in humans.

00:10:27The bubal has an amazing

00:10:29escape tactic.

00:10:31To escape other animals,

00:10:33they move in a zigzag.

00:10:35The great dolphins have names

00:10:37for their congeners.

00:10:39Hey, Bob! Hey, Charlie!

00:10:41Hey, Dolly!

00:10:43Hi, guys, and thanks for the fish!

00:10:45Giraffes have a long black tongue.

00:10:47Scientists suppose that this color

00:10:49could protect the tongue from sunburns.

00:10:51Well, that's all I have for today.

00:10:53See you soon!

00:10:55Sorry to take it from you,

00:10:57but money isn't really made of paper.

00:10:59Which also proves that it doesn't grow on trees.

00:11:01American banknotes, for example,

00:11:03are made up of 25% linen

00:11:05and 75% cotton.

00:11:07That's why they have such a distinct texture

00:11:09and look.

00:11:11In the 19th century,

00:11:13money was made of paper,

00:11:15so people could easily

00:11:17counterfeit it, unlike today.

00:11:19The Eiffel Tower is almost 15 cm

00:11:21higher during the summer.

00:11:23When you heat a substance,

00:11:25its particles start to move more actively

00:11:27and occupy a larger volume.

00:11:29This is called thermal expansion.

00:11:31When the temperature drops,

00:11:33the substance contracts again.

00:11:35This effect is more significant in gases,

00:11:37but it can also be seen

00:11:39in liquids and solids,

00:11:41including iron.

00:11:43That's why when you build

00:11:45large structures, like bridges,

00:11:47you use expansion joints.

00:11:49They allow the structure to have

00:11:51a certain margin of maneuver

00:11:53to expand and contract,

00:11:55and these changes do no harm.

00:11:57Honey can last thousands of years

00:11:59without deteriorating.

00:12:01Bees land on flowers

00:12:03and transport it to their hives

00:12:05and transfer it to other bees.

00:12:07These bees reduce the water content

00:12:09of the nectar by swallowing

00:12:11and regurgitating the liquid

00:12:13several times.

00:12:15Special enzymes in their stomach

00:12:17break down the glucose in the nectar

00:12:19and it becomes more acidic.

00:12:21Bees deposit this nectar in the alveoli

00:12:23and start to lift it with their wings

00:12:25so that the water evaporates faster.

00:12:27Honey is now very acidic

00:12:29and poor in water,

00:12:31which preserves it from deterioration.

00:12:33Bacteria that cause food deterioration

00:12:35cannot survive in such conditions.

00:12:37In the past, people did not

00:12:39lift their mattresses from the ground.

00:12:41This practice began in ancient Egypt

00:12:43and continued in many other cultures.

00:12:45People realized that it was

00:12:47colder on the ground

00:12:49and that they could heat their beds

00:12:51more easily if they were not

00:12:53directly in contact.

00:12:55In the past, houses also had

00:12:57more air flow.

00:12:59So people had to find

00:13:01other ways to warm up.

00:13:03However, the hot air tended to rise

00:13:05so by placing their beds higher

00:13:07they were not as cold as on the ground.

00:13:09In addition, in this way,

00:13:11they could keep their beds cleaner more easily.

00:13:13Indeed, in modest homes,

00:13:15the floors were much dirtier than today

00:13:17and all this dirt generally migrated

00:13:19into the beds.

00:13:21Speaking of cleanliness,

00:13:23do you think people are naturally

00:13:25clean and tidy?

00:13:27In ancient Egypt, people already used latrines

00:13:29and combed their hair with combs.

00:13:31They kept their interiors and bodies clean.

00:13:33Our natural need for hygiene

00:13:35and cleanliness is motivated

00:13:37by our sense of disgust.

00:13:39It is this mechanism that helps

00:13:41our body to remain safe

00:13:43and protects it from various infections.

00:13:45This is why we are more sensitive

00:13:47to certain smells and certain things.

00:13:49But we still have rather unhealthy habits.

00:13:51For example, eating an anca

00:13:53on top of a keyboard.

00:13:55Some animals are even more well-groomed than us.

00:13:57Insects, for example,

00:13:59like to keep their environment well-organized.

00:14:01Some of them even use

00:14:03their muscular necks and triangular heads

00:14:05to sweep the dirty grass when they hunt.

00:14:07Many animals like to clear their path

00:14:09when they go in search of their future meal.

00:14:11And reptiles are one of them.

00:14:13Less vegetation increases their chances

00:14:15of catching food.

00:14:17Birds also like to clean up

00:14:19and get rid of unconsumed food,

00:14:21eggshells and any other waste in their nests.

00:14:23In this way,

00:14:25they also make them less visible

00:14:27to their predators.

00:14:29Meanwhile, in space,

00:14:31the shadows are darker on the Moon

00:14:33than on our planet.

00:14:35This is because the Earth's atmosphere

00:14:37scatters more sunlight.

00:14:39But if you could visit the Moon,

00:14:41you would see shadows so dark

00:14:43that you would not be able to see where you are going.

00:14:45You would also notice footprints

00:14:47on the lunar surface.

00:14:49Humans have not set foot on it

00:14:51until yesterday.

00:14:53As there is no water or wind on the Moon,

00:14:55nothing can erase these footprints.

00:14:57They can therefore remain there

00:14:59in their original form for millions of years.

00:15:01The core of the Earth

00:15:03contains enough gold

00:15:05to cover the entire planet.

00:15:07And if you decide to do it,

00:15:09the level of this precious metal

00:15:11would reach the height of your knees.

00:15:13For thousands of years,

00:15:15people have been exploiting gold and platinum

00:15:17as well as a lot of other precious minerals

00:15:19This is why we may have exhausted

00:15:21some minerals in some regions.

00:15:23But the Earth still has a huge number

00:15:25of these deposits,

00:15:27especially as it approaches its core.

00:15:29It is because of the countless meteorites

00:15:31that collided with our planet

00:15:33during the period of its formation.

00:15:35These meteorites contained different minerals,

00:15:37including gold.

00:15:39At the time, the Earth was still in a state of fusion.

00:15:41This is why most gold,

00:15:43a heavy element,

00:15:45sank deeply into its core.

00:15:47The gold deposits above the core

00:15:49have trapped colossal amounts of gold

00:15:51and other minerals.

00:15:53Unfortunately, most of them

00:15:55are clearly out of reach today,

00:15:57since we are talking about 2,900 km

00:15:59under the surface and temperatures

00:16:01of several thousand degrees.

00:16:03If you were about to go into space,

00:16:05one of the first things you would think

00:16:07would be your space suit.

00:16:09But do you know that it is possible

00:16:11to survive in space

00:16:13even if you do not wear any protection?

00:16:15Don't worry, you won't last more than 15 seconds.

00:16:19It is the time you need to lose consciousness

00:16:21because oxygen will no longer reach your brain.

00:16:23In 1965,

00:16:25a technician accidentally

00:16:27depressurized his suit

00:16:29inside an empty room.

00:16:31He lost consciousness after 12 to 15 seconds.

00:16:3327 seconds later,

00:16:35his suit was fortunately repressurized.

00:16:37The man said later

00:16:39that he remembered that the humidity

00:16:41on his tongue was beginning to boil.

00:16:43He also lost his sense of taste

00:16:45and he came back to himself

00:16:47only four days after the accident.

00:16:49You can't hold your breath in space either,

00:16:51so it won't save you.

00:16:53Your lungs would eventually break

00:16:55at some point because the air inside would expand.

00:16:57Oxygen in other parts of your body

00:16:59would also begin to expand,

00:17:01which means that you would inflate

00:17:03up to twice your normal size.

00:17:05A bit like Harry Potter's Aunt Marge.

00:17:07It is only thanks to your elastic skin

00:17:09that you will not explode.

00:17:11It will continue to hold you in one piece

00:17:13and the liquids of your body

00:17:15will also begin to evaporate quite quickly.

00:17:17We're having fun here, aren't we?

00:17:19The ocean owes its emblematic blue color

00:17:21to the light of the sun.

00:17:23When the sun shines,

00:17:25the water absorbs the highest wavelengths

00:17:27of orange light and red light

00:17:29and reflects the shortest luminous waves

00:17:31of blue light.

00:17:33This is only possible when there is a huge amount of water.

00:17:35So, the more water you have in one place,

00:17:37the more it turns blue.

00:17:39This is why the water you pour into your glass

00:17:41does not have this beautiful ocean blue color.

00:17:45The ocean has many important functions.

00:17:47First of all, it produces

00:17:4950 to 80% of all the oxygen

00:17:51on our planet,

00:17:53which means that it keeps us alive.

00:17:55But it also helps the Internet to work.

00:17:57So, when you are folded in half

00:17:59watching a hilarious dog video

00:18:01or watching your favorite show,

00:18:03you can thank the oceans.

00:18:05Most of the cables that power the Internet

00:18:07and allow people from all over the world

00:18:09to use it,

00:18:11go underwater.

00:18:13These are underwater communication cables,

00:18:15kilometers of cables

00:18:17that run through the bottom of the ocean.

00:18:19There are special boats

00:18:21to put all this in place.

00:18:23They are specially designed for this purpose.

00:18:25To make sure that nothing damages the cables

00:18:27and your Internet,

00:18:29you have to put them on relatively flat extensions

00:18:31at the bottom of the ocean.

00:18:33The cables must also be away

00:18:35from large oceanic ecosystems.

00:18:37Some of these cables have a special coating

00:18:39that protects them from damage.

00:18:41Thus, no hungry shark

00:18:43or any curious fish

00:18:45has the opportunity to nibble the cabling.

00:18:47Trees speak.

00:18:49Well, not exactly like people,

00:18:51but they have their own mode of communication.

00:18:53Their roots are connected

00:18:55by an underground mushroom network.

00:18:57Thanks to this network,

00:18:59trees can share their resources with each other.

00:19:01This is how they speak.

00:19:03They use these mushrooms

00:19:05to transmit nutrients and water

00:19:07from one tree to another.

00:19:09For example,

00:19:11if a tree is stronger and older

00:19:13than the other trees in the forest,

00:19:15it will share some of its nutrients

00:19:17and sugars with the small trees

00:19:19that grow nearby.

00:19:21Thanks, Dad!

00:19:23Look at all these insects

00:19:25flying through a beautiful sunny day.

00:19:27Do you think they sunbathe?

00:19:29No, because creatures that spend

00:19:31too much time outside

00:19:33can catch a sunburn.

00:19:35Insects that live underground

00:19:37and in water,

00:19:39as well as nocturnal creatures,

00:19:41have a paler and thinner skin.

00:19:43If they spend too much time outside

00:19:45during the day,

00:19:47they can catch a sunburn

00:19:49or, even worse,

00:19:51they could be eaten.

00:19:53Hey, can you speak louder?

00:19:55I just ate a whole pizza.

00:19:57It's because after a big meal,

00:19:59the skin is a little thinner.

00:20:01During digestion,

00:20:03most of our blood circulation

00:20:05is directed to the stomach,

00:20:07which deprives all other organs.

00:20:09So, the next time you want to listen

00:20:11to your favorite band during a concert,

00:20:13make sure you eat a lighter meal

00:20:15so that your stomach is optimal.

00:20:17In addition to our stomach

00:20:19and our left kidney,

00:20:21we have a magic organ

00:20:23that can grow back

00:20:25if we remove some of it.

00:20:27It begins to multiply

00:20:29as soon as the liver is damaged.

00:20:31The gravity of the injury

00:20:33determines if the liver can regenerate completely

00:20:35and how long it will take to do so.

00:20:37Have you ever wondered

00:20:39what is the worst thing for your body?

00:20:41Not sleeping or not eating?

00:20:43It turns out that lack of sleep is more dangerous.

00:20:45Indeed, if you don't rest,

00:20:47your body is exposed

00:20:49to much more risk.

00:20:51After 24 hours without sleep,

00:20:53you can start having memory problems

00:20:55and you can't concentrate.

00:20:57After only 17 hours without sleep,

00:20:59you start to feel tired and dizzy,

00:21:01irritable, tense and more emotional.

00:21:03OK, I need a nap.

00:21:05Your pain receptors

00:21:07also become more sensitive,

00:21:09which means that everything

00:21:11hurts you a little more than normal.

00:21:13Oh, and it also affects your hearing.

00:21:15What?

00:21:17On the other hand,

00:21:19you can have your first 24-hour period

00:21:21without food,

00:21:23because you stopped eating.

00:21:25During the first 8 hours,

00:21:27you continue to digest the last meals you took.

00:21:29After these first hours,

00:21:31you start using the stored fats

00:21:33as a source of energy.

00:21:35If you don't eat for more than 24 hours,

00:21:37your body will start eating

00:21:39its own proteins,

00:21:41which means that you will literally

00:21:43start losing muscle.

00:21:45Rainwater is not always drinkable.

00:21:47It can sometimes contain dangerous bacteria

00:21:49and viruses.

00:21:51It can also contain other harmful substances.

00:21:53Some communities

00:21:55only depend on rainwater

00:21:57as their main source of hydration.

00:21:59But does rainwater have any health benefits?

00:22:01Not really,

00:22:03according to current studies.

00:22:05Some of these dangerous substances

00:22:07can be eliminated from rainwater

00:22:09if you boil it,

00:22:11but it is preferable to be careful

00:22:13and to drink only water

00:22:15that comes from sources

00:22:17without any risk to human consumption.

00:22:19Rainwater can be used

00:22:21to increase body temperature

00:22:23and to add a little humidity,

00:22:25like the one we need

00:22:27in the palm of our hands

00:22:29to have a better grip.

00:22:31But sweat doesn't just appear

00:22:33on our skin,

00:22:35it comes out of about 5 million pores

00:22:37on our body.

00:22:39We literally walk on

00:22:41a quarter of our bones every day.

00:22:43Our body has a little over 200 bones,

00:22:45but about a quarter of them

00:22:47are in our eyes.

00:22:49Our eyes produce tears

00:22:51for many reasons,

00:22:53like to protect ourselves from infections

00:22:55or to eliminate debris such as

00:22:57smoke and dust,

00:22:59or when your baby makes you miserable.

00:23:01But the amount of tears we produce

00:23:03is quite surprising,

00:23:05up to 113 liters per year.

00:23:07It's almost enough to fill a bathtub.

00:23:09Wow, it's overwhelming!

00:23:11Our blood pressure

00:23:13wakes up hours before us.

00:23:15Our blood produces hormones

00:23:17such as adrenaline and noradrenaline.

00:23:19They help us boost our energy

00:23:21during the morning hours,

00:23:23but they also increase our blood pressure,

00:23:25which is generally higher

00:23:27between 6 a.m. and noon.

00:23:29During the night,

00:23:31as we should technically sleep

00:23:33and do no physical activity,

00:23:35our blood pressure drops to 20%.

00:23:37Speaking of vital fluids,

00:23:39our blood represents about 10%

00:23:41of the total weight of our body.

00:23:43Many people think

00:23:45that our body weight

00:23:47is mainly made up of muscles,

00:23:49fat reserves and bones,

00:23:51but there is much more than that.

00:23:53For an adult in good health,

00:23:55bones represent 15%

00:23:57of the total weight of the body.

00:23:59Muscles represent

00:24:01about 40 to 45%,

00:24:03fat deposits about 15%,

00:24:05and the rest is composed of elements

00:24:07such as skin, tendons, hair

00:24:09and other nice little things.

00:24:11Yes, 100%!

00:24:13Your lungs are not twins,

00:24:15they are brothers and sisters.

00:24:17Indeed, they are not the same size

00:24:19or the same shape.

00:24:21Your right lung is bigger

00:24:23and tends to weigh more,

00:24:25and it is your heart that is responsible

00:24:27because your heart is tilted

00:24:29a little to the left.

00:24:31This creates a small cavity

00:24:33in the left lung

00:24:35called the cardiac embrace.

00:24:37The right lung may be bigger

00:24:39and the left lung may be smaller.

00:24:41Many measurements of your body

00:24:43are quite symmetrical in a surprising way.

00:24:45If you stretch your arms,

00:24:47your waist, and you measure them,

00:24:49you should see how big you are.

00:24:51Based on these similar measurements,

00:24:53specialists can even develop theories

00:24:55about the appearance of ancient humans.

00:24:57It would seem that we have evolved

00:24:59to become more and more symmetrical

00:25:01to appear more attractive

00:25:03and in better health

00:25:05to attract partners.

00:25:07By stretching on two legs,

00:25:09our symmetrical characteristics

00:25:11help us move with as little energy as possible

00:25:13because they create a balance.

00:25:15Humans are not natural champions

00:25:17in terms of odour,

00:25:19but our nose can detect

00:25:21about a trillion different odours.

00:25:23Scientists continue to do research

00:25:25on this subject and think

00:25:27that this figure could be even higher.

00:25:29Some breeds of dogs are able

00:25:31to perceive odours between 10,000

00:25:33and 100,000 times higher than ours.

00:25:35But it turns out that the best-nosed

00:25:37of the animal kingdom could be the elephant

00:25:39because of the quantity

00:25:41and the stupefying number

00:25:43of olfactory receptors that it has.

00:25:45More than 10,000,

00:25:47while humans and chimpanzees

00:25:49have less than 400.

00:25:51We tend to consider our little fingers

00:25:53as our most delicate fingers,

00:25:55but they have more power than we think.

00:25:57It turns out that in case of loss

00:25:59or failure of the ear,

00:26:01the overall strength of our grip

00:26:03is about 50%.

00:26:05The liquid contained in our stomach,

00:26:07composed of chlorhydric acid,

00:26:09potassium chloride,

00:26:11and sodium chloride,

00:26:13is much more powerful

00:26:15than any acid food you can think of,

00:26:17like lemons, pineapples,

00:26:19or tomatoes.

00:26:21The pH of the healthy gastric acid

00:26:23must be between 1 and 3,

00:26:25that is, just below

00:26:27that of the acid of a battery.

00:26:29The strands of our hair

00:26:31are carried on them

00:26:33to reproduce their strength

00:26:35on human-made materials.

00:26:37Healthy hair should be able

00:26:39to withstand a weight of 12 tons.

00:26:41This is due to a small protein

00:26:43contained in the strands of hair,

00:26:45keratin,

00:26:47which is also found

00:26:49in nails and skin.

00:26:51Only one third of humans

00:26:53have a perfect vision.

00:26:55The glasses and contact lenses

00:26:57are much more numerous

00:26:59than our eyes.

00:27:01Our vision also deteriorates

00:27:03with age.

00:27:05When we are born,

00:27:07our head is one quarter

00:27:09of our total length.

00:27:11When we are 25,

00:27:13our head is only

00:27:15one eighth of this length.

00:27:17This is explained by the fact

00:27:19that the size of our head

00:27:21does not change much

00:27:23as we age,

00:27:25unlike the rest of our body,

00:27:27the human brain can contain

00:27:29five times more information

00:27:31than the Britannica encyclopedia.

00:27:33We have not yet determined

00:27:35the exact amount of data

00:27:37it can support,

00:27:39but in terms of electronics,

00:27:41the brain's storage capacity

00:27:43is about 2,500 Teraoctets.

00:27:45For comparison,

00:27:47the National Archives of Great Britain,

00:27:49which has more than 900 years of history,

00:27:51only take 70 Teraoctets.

00:27:53This is probably the reason

00:27:55why we breathe more oxygen

00:27:57than other organs,

00:27:59about 20% of the total oxygen

00:28:01that enters the bloodstream.

00:28:03However, it only represents

00:28:052% of our body mass.

00:28:07Our normal activities

00:28:09and the effect of gravity

00:28:11cause the cartilage of our ankles,

00:28:13knees, hips, back and neck

00:28:15to compress slowly.

00:28:17Once you have rested during the night,

00:28:19the cartilage returns to normal.

00:28:21On average, you are about

00:28:231.5 hours in the night.

00:28:25This is why we sleep in a lying position.

00:28:27At the airport,

00:28:29you are usually asked

00:28:31to take your laptop out of your backpack

00:28:33and put it in a separate bin

00:28:35while you pass security check.

00:28:37Laptops are dense

00:28:39and X-rays cannot see through.

00:28:41So you could hide something dangerous in there.

00:28:43If it is taken out and put aside

00:28:45in a separate bin,

00:28:47it is easier for scanners

00:28:49to detect a potential danger.

00:28:51If your phone is green,

00:28:53your e-messages are blue.

00:28:55But look, this time it is green.

00:28:57Don't panic.

00:28:59It is not as if the user

00:29:01had blocked you or anything.

00:29:03You just sent a normal SMS

00:29:05and not an e-message.

00:29:07E-messages can only be sent

00:29:09to people who own an Apple device.

00:29:11So if the recipient does not have one,

00:29:13they will all be green.

00:29:15Another reason why your phone

00:29:17could choose an SMS

00:29:20The sockets you insert into your devices

00:29:22are equipped with small plastic rings

00:29:24that separate different sections.

00:29:26These sections are called brushes

00:29:28and each of them has a different function.

00:29:30Each chip will have at least

00:29:32one plastic ring

00:29:34because each socket must be separated

00:29:36into at least two brushes.

00:29:38One of them is there to cancel

00:29:40any interference and the other

00:29:42to transport the signal.

00:29:44If, for example, your headphones

00:29:46have one ring and two sections,

00:29:48they deliver the same sound

00:29:50to your right ear and your left ear.

00:29:52If there are two rings and three parts,

00:29:54then there is the basic ring

00:29:56to cancel the interference

00:29:58and the two others for each ear.

00:30:00Three rings and four sections

00:30:02mean that you have a set.

00:30:04One for each ear

00:30:06and the last one is the microphone brush.

00:30:10I bet you've never noticed

00:30:12but all credit cards,

00:30:14whatever bank or country

00:30:16have exactly the same size.

00:30:18The very first credit card

00:30:20was issued in 1958

00:30:22by the Bank of America

00:30:24and then the international standard

00:30:26was established for emitters

00:30:28around the world to do the same.

00:30:30The standard dictates both

00:30:32the proportions and the thickness.

00:30:34Whistles can work perfectly

00:30:36even if they don't have this ball inside.

00:30:38Yet many have it.

00:30:40It's because even if there is

00:30:42sound without the ball,

00:30:44the sound is very flat

00:30:46and not very distinct.

00:30:48When you whistle,

00:30:50the ball starts to move inside

00:30:52which creates different tones

00:30:54and makes the sound more perceptible.

00:30:56Jeans have these metal rivets

00:30:58since they were invented.

00:31:00Jacob Davis, the man who made

00:31:02the first pair of jeans,

00:31:04added leather rivets

00:31:06to the places where the pants

00:31:08were most likely to tear

00:31:10to make them more solid.

00:31:12A basketball has small dots

00:31:14all over its surface

00:31:16and they serve as friction points.

00:31:18It is important that the ball

00:31:20does not slip from the hands.

00:31:22At one time,

00:31:24basketball was played

00:31:26with a football ball.

00:31:28The ground was very slippery

00:31:30and it was impossible to play

00:31:32because you had to be very careful

00:31:34to keep the ball in place.

00:31:36So they had to design it again.

00:31:38The more contact points

00:31:40there are with the ball,

00:31:42the more friction there is

00:31:44and the less chance

00:31:46there is to slip on it.

00:31:48The holes at the end of the sleeves

00:31:50do not only serve to suspend

00:31:52the pans.

00:31:54You can also place your spatula

00:31:56at this level when you prepare a meal.

00:31:58It will be held just above the pan

00:32:00and the sauce will not flow.

00:32:02However, make sure to remove

00:32:04the sauce or food beforehand

00:32:06so that it does not drip

00:32:08You empty your dishwasher

00:32:10and while everything is dry,

00:32:12your plastic containers are still wet.

00:32:14It looks like they never dry

00:32:16and it is the case.

00:32:18The reason is the material.

00:32:20Ceramic dishes heat up

00:32:22and cool down slowly

00:32:24and the remaining water evaporates

00:32:26and dries easily.

00:32:28When you take out these plastic containers,

00:32:30they cool down much too quickly.

00:32:32The water does not evaporate from the surface

00:32:34and stays right there.

00:32:36Another source of water

00:32:38comes from the upside-down cups

00:32:40that accumulate water at the bottom.

00:32:42But have you ever noticed

00:32:44that these cups have small notches below?

00:32:46They are used to evacuate water

00:32:48into the dishwasher.

00:32:50So these cups do not accumulate water

00:32:52when they go to the dishwasher.

00:32:54Look at the aluminum foil.

00:32:56One of its sides is always shiny

00:32:58and the other is dull.

00:33:00When we make this paper,

00:33:02we flatten it with rollers.

00:33:04So the manufacturers take two layers at a time.

00:33:06Thus, the sides facing the rollers

00:33:08remain shiny

00:33:10and those in the middle remain dull.

00:33:12English speakers

00:33:14always say 2am and 2pm

00:33:16without the reason seeming obvious.

00:33:18Why this choice of letters?

00:33:20It is simply Latin,

00:33:22which is always used for many other abbreviations.

00:33:24AM means ante meridiem,

00:33:26that is, before noon.

00:33:28PM means post meridiem,

00:33:30that is, after noon.

00:33:32The same goes for the weight

00:33:34expressed in books,

00:33:36which are noted LB

00:33:38according to the Latin expression Libra Pondo.

00:33:40Most movie theaters are red.

00:33:42And the reason is not to see better,

00:33:44but rather the opposite.

00:33:46In low-light conditions,

00:33:48red is the first color

00:33:50that comes to our eyes.

00:33:52However, this is what we want

00:33:54in a movie theater,

00:33:56to see only the screen.

00:33:58In addition, movie theaters

00:34:00have another reason.

00:34:02Have you ever wondered

00:34:04why so many Disney characters

00:34:06wore white gloves?

00:34:08Well, at the time when animation films

00:34:10were in black and white,

00:34:12putting white gloves on characters

00:34:14was a way to get the hands out

00:34:16of the rest of the body.

00:34:18Then, animation evolved,

00:34:20but gloves remained a Disney tradition.

00:34:22But there are also other reasons.

00:34:24These anthropomorphic hands

00:34:26make animal characters more human

00:34:28These gloves are much easier to animate,

00:34:30which speeds up the process.

00:34:32Cats often rub their bodies

00:34:34against your legs,

00:34:36but do you know why they do it?

00:34:38This way, they transfer their smell to you.

00:34:40They mark you as being their human

00:34:42and being part of their territory.

00:34:44It is also a sign of affection.

00:34:46By doing this, they show you

00:34:48that you belong to their intimate circle.

00:34:50You wonder why it is so difficult

00:34:52to kill a fly?

00:34:54Well, for a fly, we are as slow

00:34:56as lazy people.

00:34:58It is because they perceive things

00:35:00in slow motion compared to us.

00:35:02Each species has its own perception

00:35:04of speed.

00:35:06The perceived speed will be twice as fast

00:35:08for a turtle compared to us,

00:35:10and it will be four times slower

00:35:12for a fly.

00:35:14Play a video at a speed of 0.25x

00:35:16and imagine that someone approaches you

00:35:18at this rate.

00:35:20Well, that's how a fly sees you.

00:35:22So yes, it has enough time to escape.

00:35:24Each shape has different colors

00:35:26to send different signals to your brain.

00:35:28The round shapes are more friendly

00:35:30and the square shapes seem familiar

00:35:32and reassuring.

00:35:34They are therefore generally associated

00:35:36with regulation.

00:35:38Triangles reflect instability

00:35:40and are therefore generally

00:35:42warning signals.

00:35:44And finally, the STOP panel

00:35:46has a very particular octagonal shape,

00:35:48the most atypical and the most disturbing.

00:35:50It is supposed to attract your attention.

00:35:53Some sidewalks have small plates

00:35:55with bumps.

00:35:57We don't pay much attention to them,

00:35:59but they are very important

00:36:01for visually impaired people.

00:36:03They indicate a slope

00:36:05which then leads to a pedestrian crossing.

00:36:07There are also many patterns

00:36:09that indicate different things.

00:36:11Do you see the grades

00:36:13of the English-speaking schools

00:36:15A, B, C, D and F?

00:36:17No E, but why?

00:36:19This system of modern notation

00:36:21dates back to 1897.

00:36:23At first, there were all the letters

00:36:25from A to E.

00:36:27A meant excellent,

00:36:29B, good,

00:36:31C, average

00:36:33and D, passable.

00:36:35Below, there was an E,

00:36:37that is, a failure,

00:36:39which was sometimes confused

00:36:41with its opposite, excellent.

00:36:43So, quite quickly, it changed.

00:36:45The F, for fail,

00:36:47seems much more intuitive.

00:36:49Two flight attendants

00:36:51stand in the cabin,

00:36:53smiling at each other

00:36:55as the plane prepares to take off.

00:36:57Usually, it is a busy moment

00:36:59when passengers have to be let in

00:37:01and installed.

00:37:03But this time,

00:37:05it's time to have fun.

00:37:07Their flight is a ghost flight,

00:37:09devoid of passengers.

00:37:11If you have ever wondered

00:37:13what the crew does

00:37:15during empty flights,

00:37:17this is what they do.

00:37:19The engines turn on

00:37:21as the plane leaves the airport

00:37:23and heads for the runway.

00:37:25The flight attendants

00:37:27place the platoons on the ground

00:37:29and stand up.

00:37:31They hang on to the seats

00:37:33and wait for take-off.

00:37:35They laugh as the plane accelerates

00:37:37rapidly.

00:37:39In no time at all,

00:37:41it swallows the runway.

00:37:43As it rises in the air,

00:37:45the second plane continues

00:37:47to the end.

00:37:49A new personal record!

00:37:51Although it seems exaggerated,

00:37:53according to a safety trainer

00:37:55on the travel forum Quora,

00:37:57surfing on the runway really exists.

00:37:59People with fragile hearts

00:38:01can choose to sit on the platform

00:38:03when it slides down.

00:38:05The imagination ignites

00:38:07as to what others can do.

00:38:09Tours inside,

00:38:11wheeling in the alleys,

00:38:13discos or karaoke on board.

00:38:15If you are a flight attendant

00:38:17and your crew wants to party,

00:38:19choose a song on the seat screen

00:38:21and take the microphone.

00:38:23Your colleagues are waiting for you.

00:38:25There are no passengers around you

00:38:27to see you dance.

00:38:29Everything is allowed,

00:38:31the sky is the limit.

00:38:33A crew member made a viral video

00:38:35singing in the alley of an empty plane.

00:38:37Millions of people watched

00:38:39this eccentric video.

00:38:41It was a video about food

00:38:43intended for passengers.

00:38:45However, anyone who would

00:38:47take this kind of behavior

00:38:49would be immediately sent back

00:38:51even if he had established

00:38:53a new surfing record.

00:38:55Do you wonder

00:38:57why there are even

00:38:59ghost flights?

00:39:01The reasons are multiple.

00:39:03In Europe,

00:39:05airlines must fulfill

00:39:07their obligations and ensure

00:39:09that passengers do not

00:39:11miss their flight.

00:39:13If airlines do not

00:39:15fulfill their obligations

00:39:17at least 80% of the time,

00:39:19they risk losing their

00:39:21schedule for the benefit

00:39:23of the competition.

00:39:25Airplanes cannot stay

00:39:27at the airport all night

00:39:29as you would with a car.

00:39:31They must sometimes be prepared

00:39:33to be put in a specific place.

00:39:35In some cases,

00:39:37you may think of something

00:39:39a little scary like in a horror movie.

00:39:41And you are right.

00:39:43There are real and documented ghost flights.

00:39:45In 1943,

00:39:47a mission flight disappeared

00:39:49after a raid in Naples.

00:39:51In Libya,

00:39:53a wreck was discovered

00:39:55but only 15 years later.

00:39:57No crew member was found.

00:39:59The following year,

00:40:01a second expedition

00:40:03found fresh enough water

00:40:05The public was fascinated.

00:40:07It was a ghost flight mystery.

00:40:09For most air hostesses,

00:40:11daily experiences on an empty plane

00:40:13are not particularly scary

00:40:15or as fun as those

00:40:17of our street surfers.

00:40:19They are too busy for all that.

00:40:21When a classic plane lands,

00:40:23passengers leave it,

00:40:25leaving a mess behind.

00:40:27Not everyone is as organized

00:40:29as you and me.

00:40:31At that moment,

00:40:33we clean all surfaces

00:40:35so that the new passengers

00:40:37have a perfectly clean environment.

00:40:39They have to work quickly.

00:40:41They have a deadline to follow.

00:40:43The plane must be ready

00:40:45to take off in less than 80 minutes,

00:40:47sometimes much less,

00:40:49depending on the aircraft.

00:40:51This time is called the turnaround.

00:40:53The longer the plane stays on the tarmac,

00:40:55the less money the airline makes.

00:40:57They want the rotation time

00:40:59to be as short as possible.

00:41:01Several thousand liters are needed

00:41:03depending on the size of the plane,

00:41:05its weight and the length

00:41:07of the necessary journey.

00:41:09Without waiting for the cleaning team

00:41:11to finish, the restoration team

00:41:13enters the plane.

00:41:15They must often meet

00:41:17because the meals are stored in the kitchen.

00:41:19The meals must at least correspond

00:41:21to the number of passengers on the flight.

00:41:23Any minor repair,

00:41:25such as repairing a torn seat,

00:41:27must wait for a longer stop.

00:41:29In case of a follow-up,

00:41:31the luggage compartments are emptied

00:41:33by the staff on the ground

00:41:35while the new luggage arrives.

00:41:37Some of the most complex manipulations

00:41:39can consist of moving the luggage

00:41:41towards the rolling mats.

00:41:43There is not much space

00:41:45and sometimes the luggage carrier

00:41:47has to crouch to do his job.

00:41:49It takes a lot of strength and skill

00:41:51and time.

00:41:53The hostesses are also busy.

00:41:55They must make sure

00:41:57they are ready when the passengers arrive.

00:41:59They exercise the muscles of their faces.

00:42:01Soon, the on-board staff

00:42:03will smile all the time

00:42:05and say hello 200 times in a row.

00:42:07Although the hostesses and stewards

00:42:09are always kind,

00:42:11they have to deal with all kinds of behavior,

00:42:13which can test the patience

00:42:15of the strongest among them.

00:42:17Based on a list of 17 behaviors

00:42:19observed over the years,

00:42:21an on-board agent will make

00:42:23the following recommendations to the passengers.

00:42:26Sometimes more than 200 times in a row.

00:42:28Can you say hello to them in your turn?

00:42:30They are happy to help you,

00:42:32but recommend to the passengers

00:42:34to press the ringer only

00:42:36when it is essential.

00:42:38Agents pick up the garbage

00:42:40at precise times,

00:42:42wear gloves and prefer

00:42:44not to run in both directions.

00:42:46There is something that bothers

00:42:48most people when the passengers

00:42:50take off their shoes, the smell.

00:42:52So make sure you have

00:42:54gloves and gloves.

00:42:56On-board agents need, for example,

00:42:58to urgently use rubber slippers.

00:43:00Everyone knows the rule

00:43:02to turn off their mobile phone,

00:43:04but everyone does not know

00:43:06why it is so important.

00:43:08Suppose that all passengers

00:43:10turn on their phones.

00:43:12In this case,

00:43:14the high-frequency electromagnetic fields

00:43:16of mobile phones can disturb

00:43:18the aircraft's navigation system

00:43:20and cause false indications.

00:43:22The crew recommends

00:43:24to keep the belt fastened

00:43:26during the entire flight,

00:43:28even if the panel is off,

00:43:30because strong turbulence

00:43:32can occur unexpectedly

00:43:34and the plane can descend

00:43:36from 90 meters.

00:43:38You can loosen your belt

00:43:40to feel comfortable

00:43:42and the on-board agents

00:43:44will be happy to check

00:43:46that you are safe.

00:43:48Passengers find themselves

00:43:50in a difficult situation

00:43:52and keep your seat straight

00:43:54while food is served

00:43:56or when your neighbor

00:43:58accesses your seat.

00:44:00Passengers often leave

00:44:02their headphones on

00:44:04their ears when

00:44:06they talk to an on-board agent.

00:44:08The on-board agents

00:44:10can ask the passengers

00:44:12if they want a drink

00:44:14and they can receive

00:44:16an empty look in return.

00:44:18Passengers can wait

00:44:20until the take-off is over

00:44:22because it can be dangerous.

00:44:24Although their work

00:44:26can be tiring,

00:44:28on-board agents are patient,

00:44:30kind and friendly.

00:44:32They give everything they can

00:44:34even if they are tired.

00:44:36International flights

00:44:38can be long and tiring.

00:44:40So who could blame them

00:44:42if they find themselves

00:44:44on a ghost flight

00:44:46What would you do

00:44:48if you found yourself

00:44:50on a ghost flight?

00:44:52Dogs,

00:44:54shrimps,

00:44:56fish,

00:44:58the animal kingdom

00:45:00is full of surprises

00:45:02that prove that nature

00:45:04is amazing.

00:45:06Are you ready to discover

00:45:08incredible things

00:45:10about animals

00:45:12that you have

00:45:14never seen before?

00:45:16Let's go!

00:45:44Instead of that,

00:45:46we started to accumulate fat

00:45:48to keep the heat.

00:45:50That's why we have hair.

00:45:52We don't have fat on the skull.

00:45:54Dogs can wear dental equipment

00:45:56like humans.

00:45:58And you may not believe it,

00:46:00but it's been 30 years

00:46:02that it exists.

00:46:04Dogs can also go to the dentist

00:46:06for obturations

00:46:08in the case of curry or crown.

00:46:10The smallest primate in the world,

00:46:12it can hang on your finger

00:46:14as if it were a tree trunk.

00:46:16Seagulls are the only birds

00:46:18that distinguish blue

00:46:20and their eyeglasses

00:46:22are not exactly like humans.

00:46:24They are rather tubes

00:46:26and as they do not move

00:46:28in their orbit,

00:46:30seagulls can turn their heads

00:46:32almost completely.

00:46:34Butterflies smell with their paws,

00:46:36snakes with their tongues

00:46:38and octopuses with their tentacles.

00:46:40Aratopes live underground

00:46:42and communicate with each other

00:46:44by tapping their heads

00:46:46against the walls and tunnels.

00:46:48The color of the queen's eyes

00:46:50changes depending on the season.

00:46:52They are golden in summer

00:46:54and blue in winter.

00:46:56Bees indicate to other bees

00:46:58the location of pollen sources

00:47:00by dancing.

00:47:02The fastest human punch ever recorded

00:47:04reaches 72 km per hour.

00:47:06The punch of the shrimp

00:47:08reaches 80 km per hour.

00:47:10These creatures also have 16 types

00:47:12of photoreceptors in the eyes

00:47:14and they distinguish unimaginable colors

00:47:16for humans who have only three.

00:47:20They are also very colorful,

00:47:22even to our eyes.

00:47:24So imagine how they look.

00:47:28Pistol shrimp are even more powerful

00:47:30than their cousins.

00:47:32They close their claws at such a speed

00:47:34that a hot air bubble forms under the water.

00:47:36The temperature of this bubble

00:47:38is extreme.

00:47:40It reaches, in an instant,

00:47:42the temperature of the sun.

00:47:46To our knowledge,

00:47:48the oldest tree in the world

00:47:50was called Methuselah

00:47:52at 4,700 years old.

00:47:54It was still a young tree

00:47:56in the 20th century BC.

00:47:58Dolphins sleep with half of their brains

00:48:00while the other half remains awake.

00:48:02Horses have a heart,

00:48:04like everyone else,

00:48:06but they also have organs

00:48:08similar to the heart under each foot.

00:48:10They pump blood

00:48:12into the legs when the horse stands up.

00:48:16Some subspecies of hippocampus

00:48:18look like chameleons.

00:48:20It's not just because they change color,

00:48:22but also because each eye

00:48:24moves independently.

00:48:26Other hippocampuses

00:48:28cannot change color,

00:48:30but they are born with a color

00:48:32that corresponds to their habitat.

00:48:34Red for coral,

00:48:36and green for algae, for example.

00:48:38Flaming pink babies

00:48:40are light gray.

00:48:42The algae and seafood

00:48:44they feed on contain substances

00:48:46called carotenoids,

00:48:48and thanks to which, over time,

00:48:50flamingos get this pink plumage.

00:48:52These are the same substances

00:48:54found in carrots,

00:48:56and your skin can turn orange

00:48:58The black and white stripes

00:49:00of zebras are not useful

00:49:02to hide them from predators,

00:49:04but they allow them to avoid

00:49:06the bites of dangerous insects

00:49:08such as the tsetse fly.

00:49:10The fly sees the zebra,

00:49:12but when it approaches,

00:49:14it misses the target

00:49:16or it crashes and bounces on the animal.

00:49:18No one knows exactly why.

00:49:20According to a theory,

00:49:22the black and white fur

00:49:24of the zebra creates an optical illusion

00:49:26The giraffes see the danger in the distance.

00:49:28Their heads act as a control tower,

00:49:30and they warn the other giraffes

00:49:32of the danger in a very strange way.

00:49:34They emit a very serious whistling.

00:49:38Seagulls can drink salty water.

00:49:40They have glands

00:49:42that secrete salt right next to their eyes.

00:49:44This purifies the salty water very quickly,

00:49:46and the salt residues

00:49:48come out through the nostrils.

00:49:50The most unlikely creature in the world

00:49:52is probably the jellyfish.

00:49:54It has no sensory organs

00:49:56such as our eyes, ears and nose.

00:49:58It has no skeleton,

00:50:00but the craziest thing is

00:50:02that it has no heart or brain.

00:50:04It is almost entirely composed of water.

00:50:06That's why if you take a jellyfish out of the water

00:50:08and put it on the shore,

00:50:10it sinks.

00:50:12There are jellyfish

00:50:14that are virtually immortal

00:50:16if they remain in a safe environment.

00:50:20Limuls have two eyes

00:50:22on the sides of the head.

00:50:24Five on top of the shell,

00:50:26two near the mouth

00:50:28and one on the tail.

00:50:30The latter has a photoreceptor function.

00:50:32It absorbs light

00:50:34and allows the animal to know

00:50:36if it is day or night.

00:50:38Hippos do not sunbathe.

00:50:40They produce their own sunscreen.

00:50:42It's a kind of pink sweat

00:50:44that covers their entire body.

00:50:48Kangaroo rats can survive

00:50:50for years without water

00:50:52and sometimes their entire life.

00:50:54They live in extremely arid deserts

00:50:56and absorb all the water

00:50:58they need thanks to the seeds

00:51:00and plants they feed on.

00:51:02The green basil has the incredible ability

00:51:04to walk on water.

00:51:06First of all,

00:51:08its hind legs are provided with long fingers

00:51:10with excess skin that peels off in the water.

00:51:14The surface that comes into contact with the water

00:51:16is therefore ample.

00:51:18Then,

00:51:20the lizard starts running extremely fast,

00:51:22thus creating pockets of air

00:51:24that prevent it from sinking.

00:51:28The pogon

00:51:30is nicknamed a fireworks cracker

00:51:32for a good reason.

00:51:34When it swallows too much ostracode,

00:51:36a type of zooplankton,

00:51:38small creatures begin to shine

00:51:40inside the fish because of their bioluminescence.

00:51:44The pogon thus becomes more visible,

00:51:46even for predators.

00:51:48And so they spit out the ostracodes

00:51:50by creating this effect

00:51:52of blue fireworks.

00:51:56Opossums are immune

00:51:58to snake venom.

00:52:00The secret is a peptide that helps these animals

00:52:02to neutralize toxic substances.

00:52:04That is why opossums

00:52:06swallow snakes.

00:52:08Suricates have black spots

00:52:10around the eyes.

00:52:12They are not there simply to make them more adorable,

00:52:14they also serve as natural glasses.

00:52:18The black fur of the spots

00:52:20blocks the sun,

00:52:22and the suricates can thus look at the sky.

00:52:24The sentinel,

00:52:26the suricate that watches the surroundings,

00:52:28can thus warn the group

00:52:30in case of the presence of birds

00:52:32or other predators.

00:52:34Salmons are much better swimmers

00:52:36than many divers,

00:52:38but the competition is not balanced.

00:52:40The salmons

00:52:42can be spotted

00:52:44thanks to the Earth's magnetic field.

00:52:48The dingos have mobile hands,

00:52:50like humans.

00:52:52It is useful if they have to climb a tree,

00:52:54catch food,

00:52:56or even open doors.

00:52:58The sponge crabs

00:53:00are the most stylish in the animal world.

00:53:02They make hats

00:53:04from marine sponges.

00:53:06These hats protect them,

00:53:08allow them to camouflage

00:53:10and avoid predator bites.

00:53:14Flying squirrels

00:53:16shine under the UV light

00:53:18and emit pink light.

00:53:20They are able to absorb the light

00:53:22and send it in another color.

00:53:26The apples you are used to buying

00:53:28at the supermarket look super fresh,

00:53:30but they have sometimes been harvested a year earlier.

00:53:32Everything is in the way they are preserved.

00:53:34First, they are covered with wax.

00:53:36Then, the wax is dried in the hot air,

00:53:38and finally, the apples are stored

00:53:40in cold rooms.

00:53:42The lazy ones are stronger than the dolphins

00:53:44to hold their breath.

00:53:46These lazy ones are able to slow down

00:53:48their heart rate and thus hold their breath

00:53:50for 40 minutes.

00:53:52If they watched series to cut the breath,

00:53:54they would only breathe once per episode.

00:53:56If you look at old photos,

00:53:58you will see that people did not smile

00:54:00as much as they do today.

00:54:02First of all, because photographers

00:54:04preferred serious faces.

00:54:06So instead of saying,

00:54:08people said something like,

00:54:10and their lips remained tight.

00:54:12Other words worked just as well.

00:54:14Earth is not the only planet with water.

00:54:16NASA scientists are convinced

00:54:18that one of Jupiter's moons,

00:54:20Europe, has an ocean

00:54:22made up of twice as much water

00:54:24as our planet.

00:54:26But it is hidden under a thick layer of ice.

00:54:28And even Mars would have liquid water.

00:54:30Squirrels are among the biggest

00:54:32in the planet.

00:54:34Most species are not very impressive,

00:54:36measuring only between 2 and 5 cm long.

00:54:38It's already not bad.

00:54:40But the largest, known as

00:54:42Megapomponia imperatoria,

00:54:44measures about 7 cm long.

00:54:46And its wings have an impressive

00:54:48width of 20 cm.

00:54:50A very big animal then.

00:54:52All goats do not peacefully graze

00:54:54the grass of the meadows.

00:54:56Some prefer to climb trees to feed.

00:54:58For example, Moroccan goats

00:55:00are much more attracted

00:55:02to the fruits of the meadows

00:55:04than to ordinary grass.

00:55:06These fruits really look delicious.

00:55:08These goats are rather agile.

00:55:10They climb easily into the trees

00:55:12to pick up their juicy treats.

00:55:14And they don't need

00:55:16anyone's help to do it.

00:55:18There is a creature

00:55:20which, in principle,

00:55:22is able to live forever.

00:55:24It is a species of jellyfish

00:55:26known as Turritopsis do...

00:55:28No, it's too difficult.

00:55:30It is also called, more simply,

00:55:32the immortal jellyfish.

00:55:34These animals have the ability

00:55:36to regenerate.

00:55:38Basically, as soon as something

00:55:40goes wrong, these jellyfish

00:55:42return to the polyps stage

00:55:44and start all over again.

00:55:46Now we are going to test your knowledge.

00:55:48Are there more trees on Earth

00:55:50or stars in the Milky Way?

00:55:52If your answer is star,

00:55:54sorry, but you are wrong.

00:55:56There are 3,000 billion trees on Earth.

00:55:58Impressive!

00:56:00Pluto has not yet made a complete revolution

00:56:02around the Sun

00:56:04since it was discovered.

00:56:06And now, tell yourself that we have known

00:56:08this dwarf planet since 1930.

00:56:10It takes about 248 years for Pluto

00:56:12to make a complete tour of our common star.

00:56:14In fact, it is Mercury the fastest.

00:56:16It takes about 88 days for this planet

00:56:18to go around the Sun.

00:56:20Anyway, Pluto will complete

00:56:22its first revolution since its discovery

00:56:24in 2178.

00:56:26What a suspense!

00:56:28Another funny fact about planets.

00:56:30The dwarf planet Omea

00:56:32has a very particular shape.

00:56:34It looks like an earth apple.

00:56:36It is about the same size as Pluto

00:56:38and has rings similar to those of Saturn.

00:56:40If you want to find it one day,

00:56:42it is located somewhere beyond

00:56:44the orbit of Neptune.

00:56:46Nachos were not invented

00:56:48so long ago in Mexico.

00:56:50We have been eating it for less than 100 years.

00:56:52The name Nachos

00:56:54would have been created in the 1940s.

00:56:56There is a beautiful story

00:56:58behind the creation of Nachos.

00:57:00A regular customer who was very hungry

00:57:02that day asked Ignacio

00:57:04to bring her and her three friends

00:57:06something a little different.

00:57:08Seeing how hungry these ladies were,

00:57:10he decided to prepare something for them quickly.

00:57:12And he had to improvise

00:57:14and use the ingredients he had at hand.

00:57:16So he put tortillas,

00:57:18grated a large amount of cheese on it

00:57:20and to make the dish more tasty,

00:57:22he added some jalapeno peppers.

00:57:24Mami Finan, the customer in question,

00:57:26asked her what the name of this unknown dish was.

00:57:28Ignacio thought for two minutes

00:57:30before answering

00:57:32the specialty of Nachos.

00:57:34Oranges are not always orange.

00:57:36When they are grown in subtropical regions

00:57:38where it is not cold enough,

00:57:40the chlorophyll does not decompose

00:57:42and the skin of the fruit remains yellow or greenish.

00:57:44These oranges are generally treated

00:57:46with ethylene gas

00:57:48to give them their usual color.

00:57:50That's what makes everything orange.

00:57:52Well, now I'm going to give you a little riddle.

00:57:54What is the common point

00:57:56between peanut butter and a wedding ring?

00:57:58Diamonds, of course!

00:58:00Scientists have learned

00:58:02to turn peanut butter into diamonds.

00:58:04They extracted oxygen from CO2.

00:58:06They recovered the carbon

00:58:08and subjected it to intense pressure.

00:58:10In the end, they got diamonds.

00:58:12That's it, you know everything!

00:58:14The globefish, also called balloon fish,

00:58:16is famous for two things.

00:58:18Its incredible clumsiness

00:58:20and its ability to transform

00:58:22into a kind of balloon.

00:58:24By swelling up,

00:58:26these fish can survive in nature.

00:58:28In this state, they are inedible.

00:58:30In fact, they are not really edible

00:58:32even when they are deflated.

00:58:34Their poison is more than a thousand times

00:58:36more toxic than cyanide.

00:58:38Do not count on antidotes,

00:58:40there are none.

00:58:42Maybe we'll find some one day.

00:58:44Hot-blooded people can do it too.

00:58:46There is even one who lives in Edinburgh

00:58:48and he was made a knight in 2008.

00:58:50Here is Niels Olaf III,

00:58:52the mascot and colonel-in-chief

00:58:54of the Norwegian Royal Guard.

00:58:56How tall are you?

00:58:58I bet your feet are smaller

00:59:00than those of the Statue of Liberty.

00:59:02No statue really needs shoes.

00:59:04But if it wanted to buy

00:59:06new sneakers,

00:59:08it would have to find 879.

00:59:10It's not surprising,

00:59:12you are still 46 meters tall.

00:59:14These are our muscles

00:59:16that give us the chicken skin.

00:59:18We call these little muscles

00:59:20the hair pullers.

00:59:22They are at the base

00:59:24of each hair follicle.

00:59:26Every time it's cold,

00:59:28they contract,

00:59:30which makes our hair stand up,

00:59:32creating this chicken skin

00:59:34well known for its frills.

00:59:36You may think not to be very sporty,

00:59:38but if you have already ironed

00:59:40extreme ironing is a sport

00:59:42in which people take boards

00:59:44to iron in the most unexpected places.

00:59:46Forests, for example,

00:59:48on canoes or in the mountains

00:59:50to iron their clothes.

00:59:52Some even do it at the top

00:59:54of bronze statues or underwater.

00:59:56There are even official championships.

00:59:58Have these people never heard

01:00:00of unbreathable fabrics?

01:00:02Rap battles are not as recent

01:00:04as we usually think.

01:00:06In the late Middle Ages,

01:00:08rap battles were very popular

01:00:10in the world of hip-hop.

01:00:12They were very popular

01:00:14in the 15th and 16th centuries.

01:00:16Two opponents had to make fun

01:00:18of each other by improvising

01:00:20their lines.

01:00:22According to some cartographers

01:00:24of the language,

01:00:26we would have different areas

01:00:28for different tastes.

01:00:30But that's wrong.

01:00:32Some of our taste buds

01:00:34are more sensitive to certain tastes

01:00:36than others.

01:00:38Chameleons do not change color

01:00:40to adapt to their environment.

01:00:42It would probably be very tiring.

01:00:44In reality, it is their mood,

01:00:46temperature or intensity

01:00:48of light that influence this phenomenon.

01:00:50When chameleons relax

01:00:52and stretch their cells,

01:00:54the crystals inside them

01:00:56are affected by light.

01:00:58These reptiles use these crystals

01:01:00to communicate with each other,

01:01:02so, for example,

01:01:04chameleons have a good mood.

01:01:06They are even rather grumpy.

01:01:08Beware of the grumpy chameleon.

01:01:10Dwarfs can blush,

01:01:12just like people.

01:01:14It works the same way.

01:01:16They blush when they are angry,

01:01:18excited or when they feel bad.

01:01:20The skin of their necks and heads

01:01:22becomes all red.

01:01:24Opossums do not really sleep

01:01:26by hanging by the tail.

01:01:28It is common in cartoons

01:01:30and in some photos,

01:01:32to hang by the tail

01:01:34but only for a short time.

01:01:36Adults are too heavy

01:01:38to stay in this position

01:01:40for a long time.

01:01:42It would not be very relaxing

01:01:44for them if they tried to sleep like that.

01:01:46Hanging by the tail all night

01:01:48is even the pinnacle of the impossible.

01:01:50The pilot is not allowed

01:01:52to take the same meals

01:01:54when he works.

01:01:56Imagine that you are on a transatlantic flight.

01:01:58The plane flies over the Pacific Ocean.

01:02:00But the sauce tastes a little weird.

01:02:02It is probably normal.

01:02:04After all,

01:02:06we eat a plane meal.

01:02:08It can not taste like a star restaurant,

01:02:10can it?

01:02:12Time passes.

01:02:14Oh no! You were right.

01:02:16There was indeed a problem with the food.

01:02:18But if all passengers have the same problem,

01:02:20so do the pilots.

01:02:22To prevent that they are both sick,

01:02:24we advise the pilot

01:02:26not to take the same meal at the same time.

01:02:28So if one pilot feels sick,

01:02:30the other can take over.

01:02:32It is not an imperative rule

01:02:34enunciated by the official aviation agencies.

01:02:36But most airlines

01:02:38establish their own rules

01:02:40in the matter. It makes sense.

01:02:42The flight attendants

01:02:44have access to hidden equipment

01:02:46such as a defibrillator,

01:02:48extra oxygen, an extractor

01:02:50and an adhesive tape.

01:02:52But the most interesting equipment they have

01:02:54are undoubtedly the handcuffs.

01:02:56They protect passengers, others

01:02:58and sometimes themselves.

01:03:00In fact, the crew members

01:03:02have everything they need to neutralize

01:03:04a possible troublemaker.

01:03:06Aviator sunglasses look cool

01:03:08on pilots in movies.

01:03:10But in real life, they do not wear polarized glasses.

01:03:12First of all, they have an anti-blinding effect.

01:03:14This can cause some problems

01:03:16in the cockpit.

01:03:18A pilot must be able to read the instruments.

01:03:20But cockpit equipment such as LCD screens

01:03:22emit a polarized light.

01:03:24A pilot wearing these glasses

01:03:26will not be able to read the screens

01:03:28with a 100% efficiency.

01:03:30For safety reasons, pilots

01:03:32must not wear sunglasses.

01:03:34Imagine a dazzling reflection

01:03:36coming from the windshield of another plane.

01:03:38But the pilot missed the mark

01:03:40because of his tinted glasses. Ouch!

01:03:42Have you ever noticed a hole

01:03:44in the tail of a plane?

01:03:46Well, most commercial planes have one.

01:03:48The next time you get on a plane,

01:03:50take a closer look.

01:03:52This is the auxiliary power unit.

01:03:54From the outside, it looks like a hole.

01:03:56But it is actually a hidden turbine engine.

01:03:58Most of the time, the APU

01:04:00stays off during the entire flight.

01:04:02It starts to work when the plane lands.

01:04:04It powers the cabin lights,

01:04:06the air conditioning and all the electronics

01:04:08in the cockpit.

01:04:10But do not underestimate the performance of the APU.

01:04:12It can also provide the power

01:04:14needed to start the main engines.

01:04:16You just watched a nice video

01:04:18and you learned what the APU means.

01:04:20A perfect way to start a conversation

01:04:22in the evening.

01:04:24Unfortunately, you are not in a good mood.

01:04:26You just want to take the plane,

01:04:28land and start your holidays.

01:04:30But unfortunately,

01:04:32there is only one door to board.

01:04:34And you are in line.

01:04:36Why do planes always have

01:04:38several doors?

01:04:40According to specialists,

01:04:42the main problem is that

01:04:44the gateway takes up a lot of space.

01:04:46When a plane is loaded

01:04:48the recently renovated or built airports

01:04:50tend to have a double boarding

01:04:52compared to the old terminals.

01:04:54Change of scenery.

01:04:56Let's jump in a cruise ship.

01:04:58There are hidden passages

01:05:00and secret doors in these ships.

01:05:02These are the secrets of the initiator.

01:05:04The crew

01:05:06works most often in its reserved area.

01:05:08How can an employee go

01:05:10from one place to another

01:05:12without using the stairs and doors used by the passengers?

01:05:14Well, there is a network

01:05:16of corridors and stairs

01:05:18all around the ship used only by the crew.

01:05:20I am serious when I talk about secret doors.

01:05:22They get confused with the walls.

01:05:24They pass unnoticed

01:05:26for those who do not know where the door is.

01:05:28Maybe you can fall on it by accident.

01:05:30Here is a clue.

01:05:32Be careful of the walls near the client's stairs.

01:05:34They are in the corner.

01:05:36Tell yourself that these gigantic cruise ships

01:05:38are actually floating metal objects.

01:05:40This leads me to a funny anecdote

01:05:42about cruise cabins.

01:05:44Imagine a one-month cruise

01:05:46across several countries.

01:05:48You collect magnets on the theme of the destination

01:05:50and you decorate your cabin.

01:05:52True cruise enthusiasts know

01:05:54the magic of magnets.

01:05:56They put some magnetic hooks in their luggage.

01:05:58Use the magnetic hooks

01:06:00to add additional storage

01:06:02in your cabin.

01:06:04Hang clothes, accessories, postcards or hats.

01:06:06Whatever you want.

01:06:08Let's talk about ships.

01:06:10Why do some ships have small holes

01:06:12to keep the hull from water?

01:06:14Water accumulates over time

01:06:16in the hull

01:06:18and the hull pump evacuates it automatically.

01:06:20Ships do not have headlights.

01:06:22The use of a headlight

01:06:24could prevent accidents, right?

01:06:26If it works for cars,

01:06:28why not for ships?

01:06:30Headlights are the source of light.

01:06:32But the light that comes out of them

01:06:34bounces on the light source at some point.

01:06:36With cars, for example,

01:06:38the headlights work because the area to be lit is narrow

01:06:40and it is difficult to intervene

01:06:42if there is an obstacle on the road.

01:06:44For ships, it is extremely complicated.

01:06:46The light source must be powerful enough

01:06:48to illuminate the area the captain wants to monitor.

01:06:50Big cargo ships, for example,

01:06:52need more than 1 km to stop

01:06:54or make decisions.

01:06:56In addition, you have to imagine

01:06:58how intense the light of the ship must be

01:07:00to illuminate the entire area in front of it.

01:07:02Ships are marked with different types of lights

01:07:04called navigation lights.

01:07:06They are small but practical.

01:07:08They are arranged in a standardized way

01:07:10so that the boats can spot each other.

01:07:12What is fascinating

01:07:14is that they are not only used to spot each other

01:07:16in the dark.

01:07:18They also indicate the movements

01:07:20and directions of other ships.

01:07:22Here is an example.

01:07:24Imagine a boat equipped with two navigation lights.

01:07:26The front one is lower,

01:07:28near the deck of the ship.

01:07:30The other one, at the back, is high.

01:07:32This means that the building goes to the right.

01:07:34It can pass safely next to the others

01:07:36Trains do not have seatbelts.

01:07:38A bit strange, isn't it?

01:07:40Every time there is an accident

01:07:42linked to a train,

01:07:44this question comes up.

01:07:46Almost everywhere in the world,

01:07:48there are no seatbelts in trains.

01:07:50Several studies have been carried out on this subject.

01:07:52Some of them have created accident simulations

01:07:54and the results have been surprising.

01:07:56The use of seatbelts in a train

01:07:58could potentially increase the number of injuries.

01:08:00In cars, seatbelts are very effective

01:08:02to protect the passenger

01:08:04from being dramatically used.

01:08:06The logic behind the use of seatbelts

01:08:08is to protect the person

01:08:10when a collision causes a rapid deceleration.

01:08:12But trains have such momentum

01:08:14that they do not stop immediately.

01:08:16In a plane, passengers use seatbelts

01:08:18when taking off, landing

01:08:20and in case of turbulence.

01:08:22This is not the case for trains.

01:08:24Entering and leaving a station

01:08:26does not pose a high risk.

01:08:28Experts believe that the driver's concentration

01:08:30and regular maintenance

01:08:32of the seatbelts

01:08:34is the most important factor.

01:08:36So now you are traveling by train.

01:08:38You look out the window.

01:08:40There are small stones along the railway

01:08:42to accompany you on your journey.

01:08:44These stones are officially called

01:08:46railway ballasts.

01:08:48They play a very important role.

01:08:50They support and maintain the track.

01:08:52But they are not there by mere coincidence.

01:08:54Now look at the stones up close.

01:08:56You can see that there is not one

01:08:58well cut on the tracks.

01:09:00Each stone has sharp and abrupt stops.

01:09:02These stops cling to each other.

01:09:04They protect the railway

01:09:06from violent collisions.

01:09:08They facilitate the flow of water

01:09:10in case of heavy rain

01:09:12and prevent grass and other weeds from growing.

01:09:14Now imagine that they are replaced

01:09:16by round pebbles.

01:09:18They will slide down.

01:09:20Finally, the ballast will collapse

01:09:22and the tracks will collapse.

01:09:24This is the last thing you want,

01:09:26especially if you are a passenger on this train.

01:09:28This is your first time

01:09:30on the market in Iceland.

01:09:32Volcanic bread.

01:09:34You taste a slice

01:09:36and strangely, it's not bad.

01:09:38You don't really know how it works

01:09:40and you want to know more about its manufacturing.

01:09:42Hum.

01:09:44Is it me or this kitchen is very strange?

01:09:48The oven is located in the middle of nature

01:09:50in the middle of hot springs.

01:09:52Be careful where you put your feet.

01:09:54It would be a shame to burn yourself

01:09:56A local baker

01:09:58gives you the recipe for his

01:10:00rye bread.

01:10:02Rye flour, ok.

01:10:04Yeast, ok.

01:10:06You mix everything and put it in a metal pot.

01:10:08Then you have to dig the hole

01:10:10in which you will put the pot for cooking.

01:10:12You dig a hole of about 40 cm

01:10:14and you reach the underground water

01:10:16that boils.

01:10:18If you want to do like the natives,

01:10:20you can use your finger to take the temperature.

01:10:22Ouch! It's hot!

01:10:24It's because the ground is heated by lava.

01:10:26Iceland

01:10:28is one of the most volcanic regions in the world

01:10:30with its 30 active volcanoes.

01:10:34Then you have to bury your bread

01:10:36in this volcanic soil

01:10:38and let it cook for 24 hours.

01:10:40The next day,

01:10:42the bread is ready and it's delicious.

01:10:44Ah!

01:10:46And the best is that you just perpetuated

01:10:48an old Icelandic tradition.

01:10:50People have been doing this

01:10:52since the 19th century.

01:10:56Imagine now that it's your first day

01:10:58of work in a museum

01:11:00and that you have to clean the mask of Tutankhamun.

01:11:02You grab your cleaning utensils

01:11:04and there, oh no!

01:11:06It's not possible!

01:11:08You just broke Tutankhamun's beard.

01:11:10I don't wish it on anyone.

01:11:12But this is a true story.

01:11:14In 2014,

01:11:16an employee of the Egyptian museum

01:11:18broke Tutankhamun's beard

01:11:20and it was simply glued

01:11:22hoping that no one would notice anything.

01:11:24This mask was discovered in 1922

01:11:26and it is considered

01:11:28as one of the greatest symbols

01:11:30of our past civilizations.

01:11:32Oh, and the best part of this story

01:11:34is that historians only noticed

01:11:36the graffiti in 2016.

01:11:38If you visited the museum

01:11:40between 2014 and 2016,

01:11:42you probably saw

01:11:44a glued mask.

01:11:46If I tell you,

01:11:48what do you think of?

01:11:50A desert of sand to lose sight of, right?

01:11:52Well, according to the researcher,

01:11:54the Sahara is not always a desert.

01:11:56From time to time,

01:11:58it turns green again.

01:12:00But you probably won't be able

01:12:02to witness this event.

01:12:04Every 10,000 years, the Sahara

01:12:06goes through a humid period

01:12:08during which the sand gives way

01:12:10to lush vegetation and bluish lakes.

01:12:12This phenomenon occurs

01:12:14due to the inclination of the earth's axis

01:12:16and affects several climatic zones.

01:12:18Can you imagine the Sphinx

01:12:20surrounded by tropical forests?

01:12:22It would be incredible!

01:12:24Speaking of Sahara,

01:12:26imagine being able to return

01:12:28in 1800 BC.

01:12:30You should arrive in time

01:12:32to witness the construction

01:12:34of the black pyramid

01:12:36of the city of Dahshur.

01:12:38It is not at the same level

01:12:40as the pyramids of Giza,

01:12:42but it is a necropolis.

01:12:44The archaeologists discovered

01:12:46an important part of the black pyramid

01:12:48that had been lost for centuries.

01:12:50The Benben, also called

01:12:52Pyramidion, the tip of the Egyptian pyramids.

01:12:56A Benben is a solid block

01:12:58of limestone.

01:13:00Most of these Benben

01:13:02were covered in gold and reflected

01:13:04the first rays of sun of the day.

01:13:06Hmm, can I have a time machine,

01:13:08please?

01:13:10Do you remember the time

01:13:12when something really spicy

01:13:14and your cheeks turned red?

01:13:16Apparently, it also happens to birds.

01:13:18For example, canaries change color

01:13:20after eating peppers.

01:13:22These birds have a special pigment

01:13:24that allows them to change color

01:13:26according to their diet.

01:13:28If a canary eats red peppers,

01:13:30it turns red or orange.

01:13:32Can a rock move by itself?

01:13:34Well, it's the impression

01:13:36given by the landscape

01:13:38of Raystrike Playa in California.

01:13:40This is the bed of a dried up river

01:13:42where one of the strangest phenomena

01:13:44in the world is verified,

01:13:46moving stones.

01:13:48Imagine 40-kilo stones

01:13:50walking on sand

01:13:52more than 450 meters long.

01:13:54They were discovered

01:13:56at the beginning of the 20th century

01:13:58but no one had been able

01:14:00to see their movement

01:14:02until a recent time.

01:14:04In 2014, after a lot of research,

01:14:06researchers solved the mystery.

01:14:08The moving stones appeared

01:14:10thanks to the perfect balance

01:14:12between wind, ice and water.

01:14:14When it rains, the water falls to the ground,

01:14:16freezes and forms a layer of ice.

01:14:20The wind moves the stones

01:14:22which slide on the bed of the river.

01:14:24But if you ever visit

01:14:26Raystrike Playa,

01:14:28don't bother the stones.

01:14:30The island of Ray

01:14:32is located on the west coast

01:14:34of France.

01:14:36It attracts tourists

01:14:38looking for picturesque landscapes

01:14:40and beautiful beaches.

01:14:42But there is more.

01:14:44An extraordinary phenomenon

01:14:46occurs when two waves

01:14:48collide.

01:14:50This is what we call

01:14:52a cross sea.

01:14:54It's a bit like the sea

01:14:56turning into a chessboard

01:14:58divided into several hundred squares.

01:15:00No, it's not an optical illusion.

01:15:02The cross sea occurs

01:15:04when tourists see this phenomenon

01:15:06on the island of Ray.

01:15:08It's probably because there was a storm

01:15:10in a nearby sea.

01:15:12These agitated waters move

01:15:14in the currents

01:15:16and come in contact

01:15:18with those on the island

01:15:20producing these square patterns.

01:15:22This phenomenon

01:15:24only occurs in Israel

01:15:26and on the island of Ray.

01:15:28Nowhere else.

01:15:30Our next site

01:15:32is not far from

01:15:34the small town of Griffino

01:15:36in Poland.

01:15:38There is a pine forest

01:15:40whose trunk has a twisted base.

01:15:42If you go there during the day,

01:15:44you will probably be fascinated

01:15:46by these twisted trunks

01:15:48at an improbable angle.

01:15:50You can even use them as a stool

01:15:52if you decide to have a picnic.

01:15:54But at night, this forest

01:15:56has something worrying.

01:15:58With this little fog

01:16:00it looks strange.

01:16:02Not very welcoming.

01:16:04Science still does not know

01:16:06why the trunks have this shape.

01:16:08So, do you plan to visit during the day

01:16:10or at night?

01:16:12You go hiking

01:16:14and you find yourself caught

01:16:16in a thick fog.

01:16:18It's a shame for the photos

01:16:20but everything is not lost.

01:16:22You may have the chance

01:16:24to see a white rainbow.

01:16:26This phenomenon occurs

01:16:28because of the countless droplets

01:16:30that make up the fog

01:16:32which measure less than 50 microns.

01:16:34Instead of the colored rainbow,

01:16:36you will have a transparent arc

01:16:38whose external ends

01:16:40seem red

01:16:42and the internal ends blueish.

01:16:44Let's imagine now

01:16:46that you are walking around

01:16:48in a small village in Europe.

01:16:50You enjoy this beautiful day

01:16:52and the typical architecture.

01:16:54You go to the restaurant

01:16:56that your friend told you about.

01:16:58Ah, great!

01:17:00It's 10 minutes walk away.

01:17:02You follow the blue dot on your GPS

01:17:04and you arrive at your destination.

01:17:06Super easy!

01:17:08We love this free technology,

01:17:10don't we?

01:17:12But did you know

01:17:14that the United States

01:17:16spends more than 2 million dollars

01:17:18a day to operate its satellites?

01:17:20Yeah, it's expensive.

01:17:22Have you ever heard

01:17:24about natural snowballs?

01:17:26It's probably the proof

01:17:28that nature is perfect.

01:17:30In 2016, on the beaches

01:17:32of the Gulf of Ob,

01:17:34northwest of Siberia,

01:17:36we found hundreds

01:17:38of giant snowballs

01:17:40more than 1 meter in diameter.

01:17:42This rare but fascinating phenomenon

01:17:44occurs when the wind and water

01:17:46make small pieces of ice roll.

01:17:48The more they roll,

01:17:50the more snow they accumulate

01:17:52and the more polished they become.

01:17:54In the end, they turn into

01:17:56perfect giant snowballs.

01:17:58It's already fascinating to see one,

01:18:00but to see several of them

01:18:02in the same place,

01:18:04it's really incredible.

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