Tuesday, August 7, 2012August 7 is the birthdate of British archaeologist Louis S.B. Leakey. He and his wife, Mary (and their son, Richard), uncovered tools and fossilized bones of ancient hominines in Olduvai Gorge, Tanzania, East Africa. Their work (pictured) was critical in establishing human evolutionary development in Africa. Olduvai Gorge, "The Cradle of Mankind," is one of the world’s most important prehistoric sites. It was occupied by Homo habilis (tool user) approximately 1.9 million years ago, an ape-like human 1.8 million years ago, and Homo erectus (upright man) 1.2 million years ago. Homo sapiens (modern humans) are dated to have occupied the site 17,000 years ago.