Archaeologists Make Massive Undersea Discovery That Matches 'Sunken City' Myth

[Buster's Uncle]

Men's Journal
Archaeologists Make Massive Undersea Discovery That Matches 'Sunken City' Myth
Declan Gallagher
Sat, December 13, 2025 at 1:32 PM EST
3 min read


Off the coast of a French peninsula, archaeologists have uncovered a massive undersea wall which dates back to 5,000 B.C. and correlates with a local myth telling of a sunken city (per BBC).


Massive Undersea Wall Corroborates 'Sunken City' Legend

The 394-foot wall was built between the high and low tide marks on western edge of the Ile de Sein of Brittany. At 65 feet wide and 6.5 feet tall, it is the largest underwater structure ever discovered in the country. As water levels decreased to under 30 feet, the mythical "lost city" became visible once again. Archaeologists believe it was originally built as either a fish trap or a dam to protect against the ever-rising ocean.


'Structured Society of Hunter-Gatherers'

The wall was constructed around large granite slabs, or “monoliths,” arranged on bedrock, which were then fortified with more granite slabs and stones. Archaeologists believe that, if the wall was indeed erected for fishing, the monoliths served to support makeshift nets made from sticks and branches. According to the archaeologists’ study, published in the International Journal of Nautical Archaeology, the construction reflects "technical skills and social organization sufficient to extract, move and erect blocks weighing several tons, similar in mass to many [Neolithic] Breton megaliths.”

"It was built by a very structured society of hunter-gatherers, of a kind that became sedentary when resources permitted. That or it was made by one of the Neolithic populations that arrived here around 5,000 BC," archaeologist Yvan Pailler explained to BBC.. "This is a very interesting discovery that opens up new prospects for underwater archaeology, helping us better understand how coastal societies were organized," Pailler later told AFP (via CBS).



SAMM, 2023 / Yves Fouquet et al., International Journal of Nautical Archaeology (2025)



SAMM, 2023 / Yves Fouquet et al., International Journal of Nautical Archaeology (2025)


Site Was Originally Spotted in 2017

Per the study, there exists in the region a legend about the sunken city of Ys, which was thought to lie in the ocean off Brittany. This incredible discovery may now finally answer lingering questions about the myth. "It is likely that the abandonment of a territory developed by a highly structured society has become deeply rooted in people's memories," the study reads. "The submersion caused by the rapid rise in sea level, followed by the abandonment of fishing structures, protective works, and habitation sites, must have left a lasting impression."

Yves Fouquet, a local geologist, first made the remarkable study in 2017 after using cutting-edge radar technology to make depth charts. "Just off Sein, I saw this 120-metre (393-foot) line blocking off an undersea valley,” he explained to Le Monde. “It couldn't be natural.” However, further investigations had to wait until 2022, when seaweed in the region receded. "Archaeologists did not expect to find such well-preserved structures in such a harsh setting," Fouquet added.

https://www.yahoo.com/news/articles/archaeologists-massive-undersea-discovery-matches-183258663.html