In fall 2021, geologists made an unusual discovery in Mecklenburg Bight bay in Germany – a nearly kilometer-long row of stones on the seafloor. Located about 10 km from Rerik at a depth of 21 meters, the site contained approximately 1,500 stones arranged in such a regular pattern that a natural origin seemed unlikely.

A team of interdisciplinary researchers has now concluded the stones were probably erected as a hunting structure by Stone Age hunter-gatherers around 12,000 years ago to hunt reindeer.

This represents the first discovered Stone Age hunting structure in the Baltic Sea region. The scientists are presenting their findings in the journal Proceedings of the National Academy of Sciences.

The discovery began when researchers and students from Kiel University wanted to study manganese crusts on a ground moraine ridge forming the seafloor near Rerik. During surveying, they found the 970-meter long row of stones.

The structure consists of around 1,500 stones generally 10-30cm in diameter connecting some larger boulders up to a meter across. They reported the discovery to the Mecklenburg-Western Pomerania state office for culture and heritage preservation, which coordinated further investigation.

Located on the southwest flank of the ground moraine ridge running roughly parallel to an adjacent basin, presumably an ancient lake or marsh, the stone wall must have been built before sea levels rose significantly after the end of the last ice age around 8,500 years ago, when large areas of previously accessible landscape became flooded.

Researchers used modern geophysical methods to create a detailed 3D model of the wall and reconstruct the ancient landscape. Sediment samples from the adjacent basin helped determine the possible timeframe for construction. University of Rostock and Kiel divers also explored the underwater structure.

Our investigations indicate the submerged stone wall is unlikely natural or modern, says lead author Jacob Geersen. Excluding natural processes and a modern origin, it could only have been built after glaciation when the landscape was not yet flooded by the Baltic Sea.

At that time, the whole northern Europe population was likely under 5,000 people dependent on seasonal migrating reindeer herds for food. The wall may have been used to guide reindeer toward a bottleneck between the lake shore and wall, or even into the lake, allowing Stone Age hunters to more easily kill them with their stone tools.

Comparable prehistoric hunting structures have been found elsewhere, like in Lake Huron, Michigan where 30-meter-deep stone walls and hunting blinds were built to corral caribou. Features of the Lake Huron and Mecklenburg Bight walls align, with placement along a topographical ridge and a subparallel lake shore on one side.

As the last reindeer herds disappeared from these latitudes around 11,000 years ago with climate warming, the wall was likely built before that time, making it the oldest human structure discovered in the Baltic Sea. Though numerous coastal archaeological sites from the Mesolithic and Neolithic periods are known, this submerged site provides a rare glimpse of even earlier inhabitants atop the receding glaciers.

Researchers plan further surveys with side-scan sonar, sediment echo sounders and multi-beam echo sounders to study the wall and seafloor in more detail. University of Rostock divers and state heritage department archaeologists also aim to search the area for artifacts that could aid interpretation of this unique hunting structure from the distant past.


Kiel University | Jacob Geersen, Marcel Bradtmöller, et al., A submerged Stone Age hunting architecture from the Western Baltic Sea. PNAS 121 (8) e2312008121,

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