Enlarge / Graphical reconstruction of a Stone Age wall as it may been used: as a hunting structure in a glacial landscape. Michał Grabowski
In 2021, Jacob Geersen, a geophysicist with the Leibniz Institute for Baltic Sea Research in the German port town of Warnemünde, took his students on a training exercise along the Baltic coast. They used a multibeam sonar system to map the seafloor about 6.2 miles (10 kilometers) offshore. Analyzing the resulting images back in the lab, Geersen noticed a strange structure that did not seem like it would have occurred naturally.
Further investigation led to the conclusion
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