We took a one-hour underground walking tour through the Sterkfontein Caves’ cave system, one of South Africa’s most famous fossil sites. Located about 40 kilometres northwest of Johannesburg in Gauteng, these ancient limestone caves have yielded some of the world’s most important discoveries for understanding human evolution.
Sterkfontein forms part of the Cradle of Humankind, a UNESCO World Heritage Site since 2000. The caves are particularly famous for two extraordinary discoveries: Mrs Ples and Little Foot.
On April 18, 1947, palaeontologists Robert Broom and John Robinson discovered the skull of what became known as Mrs Ples, originally classified as Plesianthropus transvaalensis. The fossil is estimated to be around 2.1–2.5 million years old, although more recent studies suggest the deposit may be between 2.5 and 2.8 million years old. Despite the name “Mrs Ples,” skull and dental analysis suggest the individual was probably an adult male—meaning “Mr Ples” might actually be more accurate! The discovery provided important evidence that early human relatives were already walking upright long before their brains became significantly larger.
Even more remarkable is Little Foot, the most complete Australopithecus skeleton ever discovered, with around 90% of the skeleton intact. Its discovery began in 1994, when palaeontologist Ronald Clarke identified several small foot bones among museum storage boxes. He eventually traced them back to the caves and, remarkably, found the rest of the skeleton still embedded deep within the rock.
Little Foot is approximately 3.67 million years old. The skeleton was given its nickname because the first bones discovered were small foot bones. Its remarkably complete limbs provide valuable evidence that this early hominin could walk upright while still retaining adaptations for climbing.
The Sterkfontein Caves have produced an extraordinary wealth of fossils — more than a third of all known early hominin fossils discovered to date — making this underground world one of the most significant archaeological and palaeoanthropological sites on Earth.
