Olduvai Gorge (also written Oldupai Gorge) is one of the most important prehistoric sites in the world — a 48-kilometre ravine cut by a seasonal stream through the Serengeti Plain, exposing two million years of geological and evolutionary history.
It was here that Louis and Mary Leakey made their landmark discoveries of early human ancestor fossils, including Australopithecus boisei and Homo habilis, revolutionising the understanding of human evolution.
The site is now managed as a museum and research site within the Ngorongoro Conservation Area, with excellent guided tours explaining the excavation history and the significance of the fossils found here. Most Northern Circuit safari itineraries stop at Olduvai on the drive between the Serengeti and Ngorongoro Crater.