A Bronze-Age barrow and walkway. Flag Fen, a few miles outside Peterborough, is one of the most important Bronze-Age sites in Europe. Discovered in 1982 by Francis Pryor, who is now director of the Flag Fen Laboratories and Bronze Age Centre, the area is unique in that large quantities of organic material from the period, including wood and leather, have survived, pickled in the waterlogged fenland peat. The centrepiece of this astonishing site is a one-kilometre-long alignment of posts passing across what would have been a stretch of open water during the Bronze Age and linking what was then the mainland with Northey Island. Where the alignment crosses the water, there is also a huge timber platform, some two and a half acres in extent.