An Introduction to the Millennium - Revelation Ch 20

The Millennium is a 1000yr period following the second coming of Christ during which Christ reigns with His Bride (The Church) in Heaven.
During the Millennium, the Born Again Believers will reign with Christ in Heaven over Israel and the Purified Nations on Earth.
After this God will make all things New and the Son will hand the Kingdom back to the Father.
God will then reign for Eternity with His Bride (Born Again Believers) in the New Jerusalem surrounded by the New Nations (whose names were in the Lamb's Book of Life).