史前世界

Five times, the Earth has faced apocalyptic events. Cataclysms that have swept away all life forms, or almost. Each time, a handful of species has survived, establishing a new world.
　　What did these prehistoric worlds look like? What catastrophes led to their disappearance? How did our distant ancestors manage to survive the five mass extinctions that the Earth has suffered, finally giving rise to the world we know today?