Sterkfontein (Afrikaans for Strong Spring) is a set of limestone caves of special interest in paleoanthropology located in Gauteng province, about northwest of Johannesburg, South Africa in the Muldersdrift area close to the town of Krugersdorp. The archaeological sites of Swartkrans and Kromdraai are in the same area. Sterkfontein is a South African National Heritage Site and was also declared a World Heritage Site in 2000. The area in which it is situated is known as the Cradle of Humankind. The Sterkfontein Caves are also home to numerous wild African species including Belonogaster petiolata, a wasp species of which there is a large nesting presence. Numerous early hominin remains have been found at the site over the last few decades. These have been attributed to Australopithecus, early Homo and Paranthropus. Modern excavation of the caves began in the late 1890s by limestone miners who noticed the fossils and brought them to the attention of scientists. In 1936, students of Professor Raymond Dart and Dr. Robert Broom from the University of the Witwatersrand began concerted excavations. The caves yielded the first adult Australopithecine, substantially strengthening Dart's claim that the skull known as the Taung Child (an Australopithecus africanus) was a human ancestor. There was a pause in excavation during World War II, but after the war Dr. Robert Broom continued excavations. In 1947, he found a nearly complete skull of an adult female (STS 5) A. africanus (or possibly that of an adolescent male). Broom initially named the skull Plesianthropus transvaalensis (near-man from Transvaal), but it became better known by its nickname, Mrs. Ples. Mrs. Ples is now defined as a member of A. africanus. In 1997, a nearly complete skeleton of a second species of Australopithecus (StW 573) was found in the caves by Ronald J. Clarke; extraction of the remains from the surrounding breccia is ongoing. The skeleton was named Little Foot, since the first parts found (in 1995, in storage) were the bones of a foot.