Olduvai Gorge in Tanzania is one of the most important sites containing fossil evidence for human evolution. Louis and Mary Leakey pioneered research in this area. Fossils and stone tools dating back to almost 2 million years have been found here. The gorge is sometimes called the Grand Canyon of human evolution.

Photo: Jules H., http://www.flickr.com/photos/holleboom/2223563613/. Licensed under Creative Commons Attribution-Noncommercial-Share Alike 2.0 Generic