7,000-Year-Old Megalithic Wall Discovered Off Brittany Coast. 120-metre-long megalithic structure discovered near Sena Gallica 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
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. 🔱
Key Facts
- 120-metre-long megalithic structure discovered near Sena Gallica 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
Related site: Sena Gallica — view location, images, and history on the Ancient Nerds map.
Source: Evidence for a Mythical 'Lost City' Discovered: 7,000-Year-Old Stone Wall Found Under The Sea! by Ancient Architects