The Cradle of Humankind is a World Heritage Site first named by UNESCO in 1999, about 50 kilometres northwest of Johannesburg, South Africa in the Gauteng province. This site currently occupies 47,000 hectares (180 sq mi); it contains a complex of limestone caves, including the Sterkfontein Caves, where the 2.3-million-year-old fossil Australopithecus africanus (nicknamed "Mrs. Ples") was found in 1947 by Dr. Robert Broom and John T. Robinson. The find helped corroborate the 1924 discovery of the juvenile Australopithecus africanus skull, "Taung Child", by Raymond Dart, at Taung in the North West Province of South Africa, where excavations still continue.