A group of scientists from the Hebrew University of Jerusalem and the Canadian University of Toronto discovered traces of human activity dating back millions of years in the Wonderwork Cave in the Kalahari Desert in South Africa.
The cave, whose name means "miracle" in ancient African language, provides some of the earliest evidence of fire use and tool production.
The new study used burial history to survey a 2.5-meter-thick sedimentary layer that contains ashes, animal remains, tools and fires. Stone machines are the oldest tools produced by humans, and usually consist of cutting tools and self-defense tools during confrontations.
 The cave is a unique historical mine among ancient archaeological sites, as it contains tools that were first found 2.6 million years ago in Africa, and was originally formed as an ancient cavity in the rocks of the Corman hills, in South Africa.
The sediments accumulating within the cave, which reach a depth of 7 meters, reflect the natural sedimentation processes such as the deposition of water and winds as well as the activities of animals, birds and human ancestors over a period of about two million years.
The site has been studied and excavated by archaeologists since the 1940s, and research on it generates important insights into human history in the African subcontinent.