Ancient Depths Unveiled: Diving into the Enigma of 5,000-Year-Old Submerged Stone Piles in Lake Constance

Embarking on an intriguing exploration, members of the Bavarian Society for Underwater Archaeology are meticulously studying 5,000-year-old man-made stone piles concealed beneath the depths of Lake Constance—an alpine lake that gracefully spans the borders of Germany, Austria, and Switzerland.

Situated at a depth of four to six meters between the municipalities of Romanshorn and Altnau, these remarkable stone piles, often referred to as “cairns,” earned the moniker “Swiss Stonehenge” upon their discovery announcement in 2019.

A prior investigation by the Archaeology Office of the Swiss Canton of Thurgau conclusively established the artificial nature of these stone piles. Notably, they were strategically placed on post-glacial banded lake deposits and did not result from glacial debris transport.

Estimates suggest an astounding 80,000 tons of rock were painstakingly transported to construct over 200 stone piles, solidifying these monuments as one of Europe’s most extensive prehistoric construction sites.

One specific pile, positioned between Lindau and Wasserburg, has been dated to the Neolithic period, ranging from 3500 to 3200 BC. However, the purpose behind these enigmatic monuments remains a subject of speculation.

In collaboration with the Bavarian State Office for Monument Preservation, a dive team comprising technical specialists and underwater archaeologists captured a cluster of stone piles near Reutenen. Their aim is to create a detailed photogrammetric analysis through a photo mosaic.

Tobias Pflederer, leader of the exploratory team, postulates that these ancient structures might have served as platforms associated with a lakeshore cult of the dead—a theory supported by several Swiss researchers.

Urs Leuzinger from the Office for Archaeology Thurgau adds depth to this hypothesis, suggesting the possibility of platforms protruding from the water as artificial islets along the lakeshore. These islets could have been pivotal in hosting ritual activities as part of burial ceremonies, with the transition from land to water serving as a central element in these ancient rituals.