In an effort to have an animal-free alternative to the legendary "Running of the Bulls," towns throughout Spain are trading in for foam balls that can weigh as much as 660 pounds.
The event, known as "boloencierro," spares bulls from cruel conditions and is a more affordable option. The change started years ago in the mountain town of Mataelpino.
But the chase still has its danger. Recent injuries at the event are driving new discussions on safety.