Olduvai Gorge is an archaeological site located in the eastern Serengeti Plains. The gorge is a steep sided ravine roughly 30 miles long and 295 ft. deep. Exposed deposits show rich fossil fauna, many hominid remains and items belonging to the one of the oldest stone tool technologies. The time span of the objects recovered date from 15,000 years ago to over 2 million years ago.

In 1959 the skull of zinjanthropus was discovered by Dr. Leakey at the Olduvai Gorge. zinjanthropus is believed to have lived 1.8 million years ago. In the 1970's the foot-prints of animals and early hominids dating back to 3.5 million years were found by Mary Leakey at Laetoli, some 45 kms south of Olduvai Gorge.

In 1974 fossils of hominid tooth were discovered, dating back to 2.4 million years. Engaruka Site, discovered not very far from Olduvai is believed to be an ancient settlement of a later civilisation. Between half a million and a million years ago, "Homo Erectus" , who stood upright, wondered around making use of hand axes. Many such tools were found at Olduvai.

Skeletal remains of hominids on the oldest bed of the gorge are assigned to the Homo Habilis an Australopithecus Boisei families. Campsites and what is believed to be a butchery site have also been excavated from this bed. The Hominid living sites in Bed I are found mainly where streams from the volcanic highlands carried fresh water to Olduvai lake. The conditions for the preservation of the sites is mainly due to the ash falls from the nearby volcanoes. The debris found at the sites are various tools, bone and teeth from animals, mainly from fair sized antelopes. Also a loosely built circle of lava blocks was found, suggesting that crude shelters were formed here as well.

The latest of the archaeological Beds is the Naisiusiu. It lays in the bottom of the Gorge at what is now the present depth. It only has a depth of 33 ft. It contains one site that has microlithic tools and one complete Homo Sapien skeleton, both of which date to 17,000 years ago.

More than 150 different species of extinct mammals have been identified from the fossils, as well as many birds, reptiles, amphibians and fish. An on-site museum explains the archeological significance of the discoveries. This area, it seems, is indeed the "Cradle of Mankind".