The Olduvai Gorge in northern Tanzania has a geology that fossil-hunters love. A river cuts through several layers of strata with four distinct beds. Bed I, the oldest, is about 2 million years old.

Olduvai Gorge, an unassuming archaeological site in Tanzania, East Africa, has become known as one of the richest paleoanthropological places in the world. Alongside hominin fossils millions of ...