Olduvai Gorge Site in n Tanzania where remains of primitive humans have been found. Louis Leakey uncovered four layers of remains dating from c.2 million years ago to c.15,000 years ago. In 1964, he announced the discovery of Homo habilis, whom he believed to have been a direct ancestor of modern humans. The gorge, which is 40km (25mi) long and 100m (320ft) deep, runs through the Serengeti Plain.

Olduvai Gorge a gorge in northern Tanzania, in which the exposed strata contain numerous fossils (especially hominids) spanning the full range of the Pleistocene period.