EGYPT

EGYPT: A 25,000-square-mile lake—one of the largest in the world if it existed today—once waxed and waned in southern Egypt, 250 miles from the Nile. Detected using data generated by a space shuttle mission, Tushka Lake existed at various sizes from 250,000 to 80,000 years ago. It would have been directly in the path of the first modern humans migrating out of Africa, so its ancient shorelines may help guide archaeological investigation.