Bronze Age stilt houses unearthed in East Anglian Fens
http://www.cam.ac.uk/research/news/bronze-age-stilt-houses-unearthed-in-east-anglian-fens
[snip] Large circular wooden houses built on stilts collapsed in a dramatic fire 3,000 years ago and plunged into a river, preserving their contents in astonishing detail. Archaeologists say the excavations have revealed the best-preserved Bronze Age dwellings ever found in Britain. [/snip]
Why do you suppose they would have made their dwellings circular?