Overview: We discover the camp from which Vikings invaded Britain, and find groundbreaking new evidence that the world-famous Avebury stone circle isn't just a sacred site but a place where our ancestors lived and worked - a discovery that's also changing our understanding of neighbouring Stonehenge. In Staffordshire, the oldest Iron Age gold in Britain is unearthed - a set of beautiful gold torcs, mysteriously abandoned 2,500 years ago.