7,000-Year-Old Megalithic Wall Discovered Off Brittany: A 120-metre wall found off the coast of Brittany was built ~5000 BC, now submerged 9 metres underwater. Made of large granite slabs and smaller stones with upright monoliths, it's one of France's largest known underwater megalithic structures. 🔱
7,000-Year-Old Megalithic Wall Discovered Off Brittany Coast
Site mentioned
📍 Ile de Sein
Key facts
- 120-metre-long megalithic structure discovered near Ile de Sein at western tip of Brittany, France
- Structure now sits 9 metres underwater but was built 7,000 years ago at the shoreline between high and low tide
- Dating to approximately 5000 BC, placing it at the Mesolithic-Neolithic transition
- Made of approximately 3,300 tons of carefully stacked granite blocks
- Wall measures about 2 metres high and 20 metres wide on average
- Contains standing stones/monoliths up to 1.7 metres in height protruding in two parallel lines
- 59 dives conducted between 2022 and 2024, totaling approximately 35 hours of documentation
- Largest underwater structure ever found in France
- Two primary theories: fish trap for coastal fishing or protective dyke against rising sea levels
- Predates the famous Carnac stone rows by approximately 500 years
- Part of 11 separate stone structures found in the area
- Researchers suggest it indicates a sedentary population rather than mobile hunter-gatherers
- Connected to the legend of the mythical lost city of Ys, said to be swallowed by the ocean nearby
Sources
Ancient undersea wall dating to 5,800 BC discovered off French coastphys.org
Dating from between 5,800 and 5,300 BC, they lie nine meters underwater and were built at a time when sea levels were much lower than today.
Archaeologists Discover Mysterious 7,000-Year-Old Stone Wall ...smithsonianmag.com
The sturdy, well-built structure was likely constructed on dry land at a time when sea levels were much lower than they are today.
Huge undersea wall dating from 5000 BC found in France - BBCbbc.com
The 120 metre wall was either a fish-trap or a dyke for protection against rising sea-levels, archeologists believe.
News - 7,000-Year-Old Wall Found Off Coast of Francearchaeology.org
In 2017, geologist Yves Fouquet first spotted the structures, which rest under 30 feet of water, with scanning equipment. After an underwater ...
French divers hit wall that's 7,000 years old - Divernetdivernet.com
The structure is some 120m long, 20m wide and averages 2m in height. It comprises large granite slabs and smaller stones, with upright monoliths ...
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