Professor Chris Stringer looks across at a new species of human, living on the Indonesian island of Flores as recently as 18,000 years ago, during a press conference in central London. The discovery of the partial skeleton came at a cave site called Liang Bua and belonged to an individual who, while fully adult, was barely a metre tall and had a skull the size of a grapefruit.   (Photo by Johnny Green - PA Images/PA Images via Getty Images)