We left the previous entry at a gate. Our species had existed for something like a quarter of a million years, almost all of it inside Africa. It had pressed against the northern exits more than once, during the wet intervals when the desert greened, and each time it had fallen back, leaving no lasting line beyond the continent. Then, sometime around seventy thousand years ago, the corridors opened again, and this time the people who passed through kept going. Everything in this entry follows from that crossing.
