Airstalls are believed to have been created during the Middle Ages, although some argue that these tunnels date back to the Stone Age.
At present, no one knows exactly why these structures were created at all. Proponents of the idea that erdstalls date back to the Stone Age believe that these structures are a network of underground passages stretching from Scotland to Turkey.
The word “erdstall” is borrowed from the German language and can be
roughly translated as “earth stall” or “mine tunnel”. Although various
types of underground tunnels are known around the world, erdstalls have
certain features that distinguish them from other underground tunnel
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