Human ancestors have been using stone and other tools since long before the emergence of Homo sapiens approximately 200,000 years ago.[20] The earliest methods of stone tool making, known as the Oldowan "industry", date back to at least million years ago,[21] with the earliest direct evidence of tool usage found in Ethiopia within the Great Rift Valley, dating back to million years ago.[22] This era of stone tool use is called the Paleolithic, or "Old stone age", and spans all of human history up to the development of agriculture approximately 12,000 years ago
