The Xiahe mandible is a hominin fossil jaw discovered in Baishiya Karst Cave, on the northeastern edge of the Tibetan Plateau in Xiahe County, Gansu, China. It was found in 1980 by a Buddhist monk who had entered the cave to meditate. This fossil discovery demonstrated that archaic hominins were present in a high-altitude, low-oxygen environment by around 160,000 years ago. Discover, Science News and Nova all named the discovery of the mandible in their lists of top science stories of 2019.Photograph credit: Dongju Zhang