A Stone Age wall discovered beneath the waves off Germany’s Baltic Sea coast may be the oldest known human-built megastructure in Europe, researchers say.
The wall, which stretches nearly a kilometer along the seabed in Mecklenburg Bay, was spotted by accident when scientists operated a multibeam sonar system from a research vessel on a student trip about 10km (six miles) offshore.
Closer inspection of the structure, called the Blinkerwall, revealed about 1,400 smaller stones that appeared to be positioned to connect nearly 300 larger rocks, many of which were too heavy for groups of people to move.
Described as an “exciting discovery”, the underwater wall is covered by 21 meters of water, but researchers believe it was built by hunter-gatherers on land next to a lake or swamp more than 10,000 years ago.
Although the purpose of the wall is difficult to prove, scientists suspect that it served as a driving range for hunters in search of herds of reindeer.
“When you chase the animals, they follow these structures, they don’t try to jump over them,” said Jacob Geersen at the Leibniz Institute for Baltic Sea Research in Warnemünde, a German port town on the Baltic coast.
“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 Proceedings of the National Academy of Sciences.
Alternatively, the wall may have forced the animals into the nearby lake, slowing them down and making it easy for people lying in wait in canoes, armed with spears or bows and arrows.
Based on 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 large tsunami moving the rocks into place, or the rocks being carried by a moving glacier. was left behind.
The angle of the wall, which is mostly less than 1 meter high, changes direction when it meets the larger rocks, suggesting that the stacks of smaller stones were deliberately positioned to connect them. In total, the wall’s stones are thought to weigh more than 142 tons.
If the wall was an ancient hunting lane, it was probably built more than 10,000 years ago and submerged about 8,500 years ago with rising sea levels.
“This places the Blinkerwall in the ranks of the oldest known examples of hunting architecture in the world and makes it possibly the oldest man-made megastructure Europe,” the researchers said.
Geersen is now keen to revisit the site to reconstruct the ancient landscape and look for animal bones and human artefacts, such as projectiles used in hunting, which may be buried in sediments around the wall.