Flag Fen is a superbly preserved Bronze Age structure. It consisted of a causeway whose posts were arranged in five rows running in a straight line from Fengate to Northey a distance of a kilometre. In the middle of this causeway was a huge wooden platform.
The construction of this causeway started in 1300 BC (at a time when Tutankhamen ruled Egypt) and continued for 400 years.
The structure was probably a boundary as well as a causeway and may also have formed a defensive palisade to protect the richly resourced Flag Fen Basin. It is, however, likely that it was also used as a shrine or temple, as hundreds of offerings of high status and valuable items, bronze tools, weapons and jewellery, were offered to the waters between the great posts. This continued long after the causeway itself had gone out of use.