“We’ve had a major breakthrough in the Rising Star cave system,” says Professor Lee Berger, one of the world’s most prolific human fossil finders. “We’ve been on an expedition for the last six weeks,” he says, and he is about to go back for a week as we do the interview. His Twitter post makes it clear he’s bursting with enthusiasm: “it’s as exciting as 2008, 2013, 2020 and the last 5 weeks!” For a palaeonthologist who has made some of the most significant fossil finds of the last three decades, including Australopithecus sediba in 2008, something extraordinary has clearly happened. “The discoveries we’ve made were right in front of our eyes, they’re extraordinary”, but he’s not letting on yet what he’s found or what it means. “I’d have to kill you if I do,” he jokes.