Nearly 13,000 years ago millions of people and animals were wiped out, and the world plunged abruptly into a new ice-age. It was more than a thousand years before the climate, and mankind, recovered. The people of Gobekli Tepe in present-day southern Turkey, whose ancestors witnessed this catastrophe, built a megalithic monument formed of many hammer-shaped pillars decorated with symbols as a memorial to this terrible event. Before long, they also invented agriculture, and their new farming culture spread rapidly across the continent, signalling the arrival of civilisation. ...