In 1960, a villager was exploiting Petralona Cave about 22 miles southeast of Thessaloniki, Greece. Although covered in calcite and missing its lower jaw, the Petralona skull has fascinated paleoarchaeologists since its discovery decades ago. The process leverages the natural properties of uranium isotopes, including the precise half-life at which it breaks down into thorium. U-series dating isn’t possible for artifacts excavated from soil deposits because dirt is constantly adding uranium isotopes from decaying debris, erosion mixtures, and other factors. It remains to be seen if the Petralona skull will ever be linked to a clear hominin ancestor.