Eon

For the Stone was from space--but perhaps not our space; it came from the future--but perhaps not our future; and within the hollowed asteroid was Thistledown. The remains of a vanished civilization. A human--English, Russian, and Chinese-speaking--civilization. Seven vast chambers containing forests, lakes, rivers, hanging cities...

And museums describing the Death; the catastrophic war that was about to occur; the horror and the long winter that would follow. But while scientists and politicians bickered about how to use the information to stop the Death, the Stone yielded a secret that made even Earth's survival pale into insignificance.