A site in northern Tanzania which is one of the most important sites for the understanding of both human evolution and the development of the earliest tools. The gorge is 30 miles long, located on the volcanic belt of the Great Rift Valley. Louis and Mary Leakey uncovered numerous Hominid remains, animal bones, and stone artifacts from c 1.9 million years to less than 10,000 years ago. Living floors and camp sites with pebble tools, choppers, and a few artifacts made on flakes go back to the earliest date as do the bones of two primitive forms of hominid, Homo habilis and Australopithecus robustus (Zinjanthropus). Crude handaxes have been dated to c 1.2-0.5 million years ago and are accompanied by several hominid fossils of Homo erectus and Homo sapiens. Acheulian tools are found with Neanderthal remains and later beds contained a Kenya Capsian industry. No site in the world has produced a longer sequence of stone tool assemblages and of hominid fossils.