Archaeological excavation. Archaeologist sitting on a block of roof-fall against the western wall of excavations at the Blombos cave site in South Africa. This site was made famous by the discovery of pieces of ochre engraved with abstract designs, 75000-year-old beads made from Nassarius shells, and bone tools thought to be around 80,000-years-old. The markers (white labels) identify artefacts and fossils found in the different levels.