Francis Pryor has spent 30 years studying the prehistory of the Fens. He has excavated sites as diverse as Bronze Age farms, field systems and entire Iron Age villages. From 1980 he turned his attention to pre-Roman religion. In 1982, while working in a drainage dyke at Flag Fen, on the outskirts of Peterborough, he discovered the waterlogged timbers of a Bronze Age religious site. In 1987, with his wife Maisie Taylor, he set up the Fenland Archaeological Trust, which opened Flag Fen to the public. He appears frequently on TV's 'Time Team' and is the author of 'Seahenge' as well as 'Britain BC', 'Britain AD' and 'Britain in the Middle Ages'.