Ancient Underwater Megastructure Not Created Naturally, Scientists Say

This is a big deal — emphasis on "big."

Great Wall

Scientists have found a giant wall underneath the Baltic Sea — and they're pretty sure humans made it.

In a new paper published in the Proceedings of the National Academy of Sciences, the German research team who discovered the megastructure, which they've called the Blinkerwall, say they believe it was constructed for hunting on land.

As the paper penned by geoscience researchers led by Kiel University notes, some parts of the Baltic Sea basin only submerged in the mid-Holocene era, dating back between 5,000 and 7,000 years.

With sediment dating estimates putting the Blinkerwall's age at between 10,000 and 11,000 years ago during the Stone Age, scientists say the uniformity of this lengthy structure — which runs for 971 meters, or roughly 60 percent of a mile — makes it seem more likely to have been made by humans than by the movements of glaciers or tsunamis. If they're right, it could be the "oldest man-made megastructure in Europe," the paper declares.

Although the entire structure is now submerged under 69 feet of water and is located six miles off the coast of Germany in its Bay of Mecklenburg, scientists say the wall seems to have been built adjacent to the shore of a lake or bog and used as a sort of driving wall for hunting reindeer.

"When you chase the animals, they follow these structures, they don’t attempt to jump over them," first paper author Jacob Geersen explained in an interview with The Guardian. "The idea would be to create an artificial bottleneck with a second wall or with the lake shore."

Old World

Indeed, the geoscientists say in their paper that they found evidence of a second wall parallel to the larger Blinkerwall, but it's likely buried in sediments.

Although other large structures had been discovered in the Bay of Mecklenburg, it wasn't until 2021 that the Kiel team detected what they now call the Blinkerwall when out on a research expedition. Using "multibeam echosound data," they determined that it is roughly a meter high at its tallest point, which also seems to lend credence to the driving wall theory.

In a statement to CNN, paper co-author Marcel Bradtmöller of the University of Rostock emphasized just how different Northern Europe was during the era the Blinkerwall was likely built.

"At this time, the entire population across northern Europe was likely below 5,000 people," Bradtmöller explained. "One of their main food sources were herds of reindeer, which migrated seasonally through the sparsely vegetated post-glacial landscape."

If further research corroborates that the Blinkerwall is what the German geoscientists think it is, it would be a huge boon for the study of that region — and the study of the Stone Age world and the humans that populated it.

Updated to correct mistaken reference to feet rather than meters.

More on the ancient world: Scientists Find Ruins of Ancient Cities in Amazon Jungle