The Olduvai Gorge or Oldupai Gorge in Northern Tanzania is commonly referred to as "The Cradle of Mankind." It is a steep-sided ravine in the Great Rift Valley, which stretches along eastern Africa. Olduvai is in the eastern Serengeti Plains in northern Tanzania and is about 30 miles long. The gorge is named after the Maasai word for the wild sisal plant (Sansevieria ehrenbergii), commonly called Oldupaai. The name "Olduvai" was derived from early European miss-spelling of "Oldupaai" the Maasai name for the plants that grow in that area.The gorge is about 50 km long and in some places 90 metres deep. It drains the slopes of the nearby mountains plus the Serengeti Plain. Its chief claim to fame is the rich treasure-trove of human and animal fossils that it has yielded.

It has amazing landscape that resulted from the tectonic forces which created the Great Rift Valley million of years ago. Long ago the area was covered by ancient salt lake which vanished and leaving salt deposits exposed in its walls until today. The importance of this area lies on the uncovered archeological remains; fossils remains, including the bones of early hominids, stone tools, marks and a building site. Other sites within the area are Laetoli site, Lake Ndutu Sites, and Nasera Rock Shelter.

phenomenon. Technically they are known as barkan, and they result if there is sufficient dust on the ground and a unidirectional wind to blow it. The dust collects around a stone, and this collection accumulates more. The process continues, with the mound growing all the time, and then it begins to move. The crescents have their two sharp arms pointing the way the wind is going, and the whole shape is beautifully symmetrical.

The main Olduvai Beds are in a lake basin about 16 miles in diameter. The rocks under the basin date to 5.3 million years ago. There have been seven major Beds distinguished they are ranked from oldest to youngest; Bed I, Bed II, Bed III, Bed IV, the Masek Beds, the Ndutu Beds, and Baisiusiu Beds.

3,500,000 years ago, our very remote ancient ancestors walked through a landscape very like that which we see today. The volcanoes were fewer but more active then, though Ngorongoro had not yet towered high above the others. On one particular day, the volcano Sadiman puffed out a lot of grey ashes, so that the local animals left crisp, clear tracks when they walked. Some of the creatures have changed little; hares were abundant, guinea-fowl scurried about, giraffes strode regally over the plain. Others are no longer with us, such as an elephant with downward-curving tusks in its lower jaw, and Hipparion, a three-toed horse.

Through this desolate grey landscape that would later be named Laetoli travelled through hominids. Shorter than ourselves (1.2 to 1.4 metres high), they may have looked more than apes than people, but they walked on two legs. A large, a medium-sized and a small individual walked together, the medium-sized one stepping in the tracks of its large companion. A day or two later, a fresh ash-fall buried the tracks, until they were excavated in 1978. We know from contemporary fossils that the footprints were made by Australopithecus afarensis, an early hominid.

It is tempting to wonder why these ape-like, small brained creatures (450cc; our own brains average 1400cc) walked upright - could they see further afield? Did they use their hands for carrying water, food, or babies? Or did they carry sticks, stones or thorn branches to fight off neighbouring hominids, or predators? If they carried such weapons, did they use them in self-defence or to stela kills from hunters?

1,890,000 years ago, the volcano Olmoti erupted, and thick lava flows covered the area now occupied by Olduvai Gorge. burying any earlier remains beneath black basalt. A lake soon formed there, and became the focus of activity for a wide variety of animals. Its alkaline waters provided ideal conditions for fossilizing dead animals and plants falling in it. The descendants of Laetoli's upright-walkers were at Olduvai. Two different kinds of hominids left remains in the deepest level of the gorge, Australopithecus boisei and homo habilis ("handy man").

1,500,000 years ago, earth movements and faulting caused "Lake Olduvai" to be drained. At this time australopithecus afarensis was still presented, while homo habilis had evolved to homo erectus ("upright man"), our direct ancestors. This human had a bigger brain (900cc) and made better stone hand-axes. Only 17,000 years ago homo sapiens lived in the gorge.