The stone wall, recently discovered at a depth of approximately 21 meters, was built by Paleolithic people to hunt deer. It is the oldest known underwater archaeological site in Europe. The ability of Paleolithic and Mesolithic humans to build stone structures on a significant scale remains unclear. Transporting large blocks of stone is technically difficult and until recently was believed to be impossible before the emergence of agricultural societies with high population densities.

Later researchers discovered separate stone buildings from the Mesolithic period, but their preservation on land is low. But until the middle of the Holocene, the Baltic Sea was noticeably smaller than it is now, which makes it possible to discover such well-preserved ancient objects at its bottom.

Finding and examining underwater objects requires interdisciplinary approaches of archeology and marine sciences. Scientists combined centimeter-resolution sonar data, sedimentological samples and optical images from ships and autonomous underwater vehicles to investigate the Stone Age megastructure recently discovered at a depth of 21 meters in Germany’s Mecklenburg Bay in the western Baltic Sea.

Comparable Stone Age megastructures have recently become known worldwide, but are virtually unknown in Europe. The clearing became one of the oldest artificial hunting structures in the world and one of the largest known structures of the Stone Age in Europe. The results of the research were published in the journal Proceedings of the National Academy of Sciences.

The structure was a wall built by hunter-gatherer groups 10,000 years ago, but would eventually sink during the formation of the Lytoryna Sea in the modern Baltic region around 8,500 BC. Since then the wall has remained hidden in the seabed, which has led to its preservation. It’s possible that ancient people who roamed the area after the retreat of the Weichselian Ice Sheet used the wall to hunt reindeer.

Reaching just under a kilometer in length, the structure consists of 1,673 individual stones, less than a meter high, placed side by side in a manner that claims natural origin as a result of glacial migration. The researchers examined the majority of the stones using an autonomous underwater vehicle from a distance of about two metres. Scientists think that the total weight of the stones is approximately 142 tons and they occupy a volume of 52.75 cubic meters.

The dating of the wall is based solely on the fact of its location at a certain depth: it was clearly built while it was still on land. However, this dating method means that the wall could have been built anytime during both the Mesolithic and Paleolithic periods, up to 8.5 thousand years before the departure of the glacier.

Most of the stones weighed less than 100 kilograms, but scientists also identified 288 heavier stones. The largest of these had an estimated weight of 11,389 kilograms. It is interesting that it is where the direction of the stone wall changes sharply. The second, third and fourth largest stones, weighing 2,083, 2,506 and 5,792 kilograms, were placed near the western end of the wall, with the latter marking its end.

The estimated construction date and functional interpretation of the wall made it an interesting discovery not only because of its age, but also because of its potential to understand the lifestyle of early hunter-gatherer communities, especially in terms of their socio-economic complexities. Fixed hunting structures tied ancient people to specific locations on the landscape, creating socio-political and economic relationships regarding ownership, territoriality, leadership, labor pool, group size, and other social dynamics.