Once, the idea of a lost world under the sea was the stuff of legend, but now scientists are rediscovering a sunken land and piecing together the lives of the people who lived there. In Northern Europe, a huge area known as Doggerland disappeared beneath the waves and has remained underwater ever since. But evidence of this lost land is starting to emerge. In this two-hour special, learn why archaeologists believe Stone Age Europeans lived on this land and pioneered an advanced culture.