In 1933 a mysterious fossil skull was discovered near Harbin City in the Heilongjiang province of north-eastern China. Despite being nearly perfectly preserved – with square eye sockets, thick brow ridges and large teeth – nobody could work out exactly what it was. The skull is much bigger than that of Homo sapiens and other human species – and its brain size is similar to that of our own species. Historical events left it without a secure place of origin or date, until today.