The Doctor: Homo sapiens. What an inventive, invincible species. It's only a few million years since they crawled up out of the mud and learned to walk. Puny, defenceless bipeds. They've survived flood, famine, and plague. They've survived cosmic wars and holocausts. And now, here they are, out among the stars, waiting to begin a new life. Ready to outsit eternity. They're indomitable… indomitable.