Olduvai Gorge, Cradle of Humankind, writing tablet, Paranthropus, Zinjanthropus, Hornoi Habilis, skulls of two human races, Ngorongoro Conservation Area, Tanzania, Africa, by Erich Schmidt Stock Photo - Afloimages
Olduvai Gorge, Cradle of Humankind, writing tablet, Paranthropus, Zinjanthropus, Hornoi Habilis, skulls of two human races, Ngorongoro Conservation Area, Tanzania, Africa, by Erich Schmidt