Explore Nairobi and around Central Nairobi The National Museum Nairobi National Park The southern Rift Valley Share Between 400,000 and 500,000 years ago, the wide, shallow lake east of what is now Olorgasailie Prehistoric Site was inhabited by a species of hominin, probably Homo erectus of the Acheulian culture (after St Acheul in France, where it was first discovered). The site is endowed with numerous pathways, boardwalks and informative signs, and is a peaceful place to stay, though most people just stop here for an hour or two. The guided tour around the excavations (included in the entrance charge, tip welcomed) is not to be missed. The museum and accommodation are just above the excavations, on a ridge overlooking the former lake. The early people who lived at Olorgasailie made a range of identifiable stone tools: cleavers for skinning animals; round balls for crushing bones, perhaps for hurling or possibly tied to vines to be used, like gauchos, as bolas; and heavy hand axes, for which the culture is best known, but for which, as Richard Leakey writes, “embarrassingly, no one can think of a good use”. The guides tell you they were used for chopping meat and digging. This seems reasonable, but some are very large, while hundreds of others (particularly at the so-called “factory site”) seem far too small, the theory being that they were made by youngsters, practising their toolmaking. Mary and Louis Leakey’s team did most of the unearthing here in the 1940s. Thousands of the stone tools they found have been left undisturbed, in situ, under protective roofs. Perhaps the most impressive find, however, is the fossilized leg bone of an extinct giant elephant, dwarfing a similar bone from a modern elephant placed next to it. It was long hoped that human remains would also be uncovered at Olorgasailie, but despite extensive digging none has been found – providing more scope for speculation. Today, sitting with a pair of binoculars and looking out over what used to be the lake can yield some rewarding animal-watching, especially in the brief dusk. Go for a walk out past the excavations towards the gorge and you may see baboons, duiker, giraffe, eland and even gerenuk if you’re lucky – Olorgasailie is the westernmost extent of their range in southern Kenya.