From NYTimes.com

Dr. Berger said the path to the discovery began over the Christmas holidays in 2007 when he began using Google Earth to map caves in the Cradle of Humankind. On a recent visit to his office, he rotated Google Earth images of the dun landscape on his desktop, showing how he spotted the shadows and distortions of the earth that gave clues to the location of caves, often topped with wild olive and white stinkwood trees.