In the depths of the Baltic Sea lies a groundbreaking discovery, Europe’s oldest megastructure, hidden away for thousands of years. This enigmatic stone wall, uncovered by Jacob Geersen and his team, challenges our understanding of prehistoric human capabilities and opens a new chapter in the history of early European architecture.
In 2021, Jacob Geersen, a marine geologist, was conducting a class on a research vessel in the Baltic Sea when they stumbled upon a stretch of stones about half a mile (almost a kilometer) long. This was a one-week field course, and during the night shift, the students would turn on the echosounders and map the sea floor in high resolution.
During one of these routine mapping, they found this extraordinary underwater wall in the Bay of Mecklenburg, off the coast of northern Germany.
Discovery of Europe’s oldest megastructure in the Baltic Sea
At the time of this discovery, Geersen and his group didn’t know the significance of their find. However, Geersen knew this discovery was different and not caused by natural events like land movements or glacial deposits.
A year later, he returned to the site with his colleagues and a new batch of students. They used an underwater camera for closer inspection and confirmed that this wall stood up to 1.5 meters in most places. It was also made with around 1,400 smaller stones built to connect about 300 larger boulders, which were too heavy for groups of prehistoric humans to have moved.
The researchers named the wall “Blinkerwall” after a nearby underwater hill called Blinker Hill. They believe the wall dates back to the Stone Age and is estimated to be around 10,000 to 11,000 years old.
Among the researchers was Berit Eriksen, a prehistoric archaeologist who studied the movement of Northern Europe’s early occupants when the glaciers retreated after the last Ice Age (10,000 to 20,000 years ago). Like other archaeologists, she eliminated natural causes and believed it was used by early European Stone Age hunters and gatherers to guide and hunt deer by the hundreds.
An ingenious way of hunting
The wall is now under the Baltic Sea, but researchers believe that early humans constructed it on dry land about 8,500 to 14,000 years ago. Before this period, the area was covered by a large sheet of ice; afterward, sea levels rose and submerged everything. It was constructed adjacent to a lake or marsh, enabling hunters to trap deer.
“When you chase the animals, they follow these structures; they don’t attempt to jump over them,” said Jacob Geersen at the Leibniz Institute. “The idea would be to create an artificial bottleneck with a second wall or the lake shore.”
This ancient hunting technique would have slowed the animals, making them easy to pick for people lying in wait with spears and arrows.
Marcel, an archaeologist from the University of Rostock, told New Scientist’s Michael Le Page that the Blinkerwall was probably built by the Kongemose culture. This group occupied southern Scandinavia around 6,000 BCE to 5,200 BCE and used stone tools to hunt deer and boar.
Berit Eriksen also believes that the wall was made by people who had settled and were familiar with the area. “If you build a structure like that,” Eriksen told NPR, “you’re someone who knows the entire area extremely well. You’re not just moving around an unknown landscape. You don’t just hope you can find a reindeer that day. You plan. You know where the reindeer will come next year.”
Exploration of the Blinkerwall may yield more information
Ashley Lemke was not involved in this research, but believes the study makes sense. She has been involved in similar stone wall discoveries in Lake Huron in Michigan and knows first-hand how challenging underwater exploration is.
She also says modern people need to give Stone Age people the credit they deserve.
“We always think of them on the brink of starvation, trying to scrape a living out of the landscape. And that’s just not true,” Ashley says. Instead: “People in Europe were building things before Stonehenge, before these more classical structures that we think of.”
Geersen and his team plan to revisit and continue exploring the Baltic Sea archaeological site. Future excavations could reveal hunting-related activities, such as animal bones, hunting projectiles, and camps, shedding more light on the people who built the Blinkerwall.
Berit Eriksen believes they may find artifacts offering DNA or other clues. “You’d have to eat while you’re there so you can see if there are small bits of charcoal.”. In addition: “They would have defecated,” Eriksen adds. “So you can find stuff — traces of people — if you’re lucky.”
