An artificial intelligence tool has revealed hidden evidence of ancient fire at a 1-million-year-old archaeological site in Israel. Applying the technology at other sites could revolutionise our understanding of when and where humans first began controlling fire, which is widely considered to be one of the most significant innovations of all time. Archaeologists already have a few techniques for identifying whether ancient humans used fire. For instance, you can look for signs that prehistoric bones are discoloured – or that stone tools are warped – in a way that is consistent with exposure to temperatures of 450 C or more. But this sort of evidence is rarely found at sites that are more than 500,000 years old.