Hundreds of narrow tunnels called "Erdstalls" can be found throughout the Bavarian region of Germany and Austria. While most experts agree that they are medieval, no one knows why they were built or how they were used. This has led to the Erstalls being called "Central Europe's last great mystery."
Throughout history there have been many explanations for the Erdstalls. They were built by elves, or goblins live there. They were dungeons or may just be the winter quarters for local tribes. The lack of written evidence in period about the tunnels only deepens the mystery.
The tunnels go as far as 30 feet (10 meters) down and are damp and narrow, often barely large enough for a man to slip through. Dating of the scant evidence found inside the tunnels shows they were probably dug between the 10th and 12th centuries. Adding to the mystery is that except for a few notable exceptions, the tunnels are devoid of artifacts.
The size and the clean nature of the tunnels has allowed people to rule out many uses including storage, keeping livestock, or as catacombs for the dead. Some people think they were related religious or superstitious practices. Others think they were hiding places. One possiblity is that they are related to Celtic monks. Similar concentrations of tunnels have been found in other areas associated with Celtic monks in France and Ireland. [photo]