French marine archaeologists have uncovered a 120-metre stone wall off the coast of Brittany, dating to around 5,000 BC. It is the largest underwater structure ever discovered in France and may be linked to myths of a sunken city, BBC reports.
The wall lies nine metres underwater near the Ile de Sein. When built, it would have stood on the shoreline. It measures roughly 20 metres wide and two metres high, with rows of granite monoliths rising from its top. Researchers think it was either a fish-trap or an early sea defence.
The structure, weighing about 3,300 tonnes, points to a sizeable and organised Stone Age community. Archaeologist Yvan Pailler says it may have been created by sedentary hunter-gatherers or early Neolithic settlers.
The site was first spotted by geologist Yves Fouquet using modern seabed mapping. Divers later confirmed the presence of a man-made barrier.
A study in the International Journal of Nautical Archaeology suggests that such abandoned coastal structures may have inspired Breton legends of drowned settlements, including the famed lost city of Ys.
