A Stone Age wall discovered beneath waves off Germany’s Baltic coast could be the oldest known man-made megastructure in Europe, researchers say.
The wall, which stretches nearly a kilometer along the seabed of Mecklenburg Bay, was spotted by accident when scientists used a multibeam sonar system from a research vessel during a student trip to about 10 km (six miles) offshore.
Closer inspection of the structure, called Blinkerwall, revealed about 1,400 smaller stones that appear to have been positioned to connect nearly 300 larger boulders, many of which were too heavy for groups of humans to move.
The submerged wall, described as an “exciting discovery”, is covered by 21 meters of water, but researchers believe it was built by hunter-gatherers on land near a lake or swamp it more than 10,000 years ago.
Although the wall’s usefulness is difficult to prove, scientists suspect it served as a travel route for hunters pursuing reindeer herds.
“When you chase animals, they follow these structures, they don’t try to jump over them,” said Jacob Geersen of the Leibniz Institute for Baltic Sea Research in Warnemünde, a German port city on the coast. Baltic.
“The idea would be to create an artificial bottleneck with a second wall or with the lake shore,” he added.
A second wall that ran alongside the Blinkerwall may be buried in seafloor sediments, the researchers write in the Proceedings of the National Academy of Sciences.
Alternatively, the wall may have forced the animals into the nearby lake, slowing them down and making them easy prey for the humans who awaited them in canoes armed with spears or bows and arrows.
Given the size and shape of the 971 meter long wall, Geersen and his colleagues consider it unlikely that it was formed by natural processes, such as a huge tsunami moving the stones or the stones left behind by a moving glacier.
The angle of the wall, which is typically less than a meter high, changes direction when it meets the larger boulders, suggesting that the piles of smaller stones were intentionally positioned to connect them. In total, the stones of the wall would weigh more than 142 tonnes.
If the wall was an ancient hunting path, it was likely built more than 10,000 years ago and submerged by rising sea levels around 8,500 years ago.
“This places the Blinkerwall within the range of the oldest known examples of hunting architecture in the world and potentially makes it the oldest man-made megastructure in Europe,” the researchers said.
Geersen now wants to revisit the site to reconstruct the ancient landscape and search for animal bones and human objects, such as projectiles used for hunting, that may be buried in the sediments around the wall.