Riverworld

Hale, an American astronaut dies and is reincarnated with other persons who have lived throughout all of human history and end up on a mysterious planet called Riverworld. The humans are left to their own devices and create tribal fiefdoms and succumb to brutal wars and raids. A mysterious race of hooded beings oversee them - sometimes intervening, but their motives are unknown. Anyone who has ever lived and died on Earth comes here rather than the afterlife, even an extra-terrestrial called Monat, who had the unfortunate luck of dying on planet Earth in 2039. Hale leads a revolt and joins with others on a large boat to explore this mysterious new world.