The skull appears to have a remarkable backstory. According to the researchers, it was originally found in 1933 by Chinese labourers building a bridge over the Songhua River in Harbin, in China’s northernmost province, Heilongjiang, during the Japanese occupation. To keep the skull from falling into Japanese hands it was wrapped and hidden in an abandoned well, resurfacing only in 2018 after the man who hid it told his grandson about it shortly before he died. An international team led by Prof Qiang Ji at the Hebei Geo University in China drew on geochemical techniques to narrow down when the skull came to rest in Harbin, dating the bones to at least 146,000 years old. The skull has a unique combination of primitive and more modern features, with the face, in particular, more closely resembling Homo sapiens. One huge molar remains. The skull, which is 23cm long and more than 15cm wide, is substantially larger than a modern human’s and has ample room, at 1,420ml, for a modern human brain. Beneath the thick brow ridge, the face has large square eye sockets, but is delicate despite its size. “This guy had a huge head,” said Stringer.