Archaeologists Discovered a Massive Ancient 'Megastructure' Submerged Beneath the Sea

Archeologists have discovered an 11,000-year old wall lurking beneath the waves of the Baltic Sea that is thought to be the oldest known human structure in the area to date. 

Described in the Proceedings of the National Academy of Sciences, the wall is submerged more than 20 meters below the surface of the Bay of Mecklenburg, on the northern coast of Germany. Researchers think the nearly one kilometer-long megastructure was once used for hunting reindeer, and it gives them clues to how Stone Age hunter-gatherers in the region lived.

The Bay of Mecklenburg has fluctuated between high and low sea levels many times since it was carved out by the last glacial period in Europe, which ended around 11,700 years ago. Despite its tumultuous aquatic history, people settled in the region intermittently. 

In fact, the Baltic Sea is a bit of a hotspot for archeological sites, but most of them are located near Scandinavia and the Eastern Baltic. This latest find is the oldest in the German region.

Researchers came across the barricade, dubbed Blinkerwall, in 2021 while scanning the sea floor using sound waves. They then sent down an autonomous underwater vehicle and archeological divers to reveal more about the wall, and create a 3D map of it.

What they saw was a massive structure made of around 1,600 stones, some heavier than 100 kilograms. Based on its sheer size, the weight of its largest stones, and their too-perfect arrangement, researchers don’t think that the wall was made by natural forces such as flooding.

“Our investigations indicate that a natural origin of the underwater stone wall as well as a construction in modern times, for instance, in connection with submarine cable laying or stone harvesting are not very likely,” said lead author Jacob Geersen in a statement.

That means the wall could only have been made after the last European ice age but before the Baltic Sea flooded. By analyzing sediment samples from the area, Geersen and colleagues narrowed the timing of when the wall was built to between 11,700 and 11,000 years ago, or the late-Pleistocene to earliest Holocene age. 

Although it’s difficult to conclude exactly what the wall was used for, Geersen and the team believe it may have been used as a tool for hunting reindeer; Archeologists have seen similar ancient hunting structures in Greenland and North America. 

“The wall was probably used to guide the reindeer into a bottleneck between the adjacent lakeshore and the wall, or even into the lake, where the Stone Age hunters could kill them more easily with their weapons,” explained study co-author Marcel Bradtmöller, from the University of Rostock, in a statement. 

The team think there may be a second wall, running parallel to the Blinkerwall, buried below the sediment. This could have acted like a kind of funnel towards the nearby lake, where hunters in boats once lay waiting. 

They now plan to send more divers to the site in search of archeological remains that could paint a clearer picture of this Stone Age society. They’d also like to use more advanced dating techniques to figure out a precise date for when the wall was built.