7,000 Year Old Stone Wall Found Beneath the Sea in France

Archaeologists have made a remarkable discovery off the coast of Brittany in western France, where a massive 120-meter-long stone wall has been found beneath the sea, alongside several smaller ancient structures.

The submerged site, believed to be around 7,000 years old, provides new insight into prehistoric human activity along Europe’s ancient coastlines before sea levels rose.

Discovery Announced by French Researchers

The findings were announced on Thursday by researchers from the Université de Bretagne Occidentale (UBO). The team specializes in underwater archaeology and coastal heritage studies.

Yvan Pailler, a professor and archaeologist at UBO, told AFP that the discovery opens new opportunities for understanding how ancient communities adapted to changing sea levels.

“This discovery gives us a rare chance to study prehistoric coastal landscapes that are now hidden beneath the ocean,” Pailler said.

Structures Built by Early Coastal Communities

The site includes eleven granite stone structures constructed by humans. The largest of these is the stone wall, measuring approximately 120 meters in length and 21 meters wide at its base.

The structures are located about nine meters below the current sea level and were identified through detailed underwater surveys conducted between 2022 and 2024 by the Maritime Archaeology and Memory research group.

Geologist Yves Fouquet first detected signs of the structures near the island of Sein in 2017. Further investigations confirmed that the formations were man-made.

Dating Back to Prehistoric Times

Researchers estimate the structures were built between 5800 and 5300 BCE, a period when coastal settlements existed in areas that are now submerged.

Experts believe the wall and surrounding buildings may have been used as fish traps, coastal barriers, or water-management structures designed to protect early settlements from rising tides.

A Major Step for Underwater Archaeology

The discovery highlights the importance of underwater archaeology in understanding human history and environmental change. Scientists say many similar prehistoric sites may still lie hidden beneath modern seas.

Researchers plan to continue studying the site to better understand its purpose and the people who built it.