"In times long past, this planet was the home of a mighty and noble race of beings which called themselves the Krell. Ethically, as well as technologically, they were a million years ahead of humankind. For in unlocking the mysteries of nature, they had conquered even their baser selves. And when in the course of eons they had abolished sickness, and insanity, and crime, and all injustice they turned, still with high benevolence, outward toward space. Long before the dawn of man's history, they had walked our Earth, and brought back many biological specimens. The heights they had reached... But then, seemingly on the threshold of some supreme accomplishment which was to have crowned their entire history, this all-but-Divine race perished in a single night. In the two thousand centuries since that unexplained catastrophe, even their cloud-piercing towers of glass, and porcelain, and adamantine steel have crumbled back into the soil of Altair IV, and nothing, absolutely nothing remains above ground."