Erdstall (tunnel)

Erdstall or erdställe (from German: erd, "Earth" + stall, "stall, stable") is a term for a type of man-made underground earthen tunnel, typically very narrow, that was constructed in various locations across Central Europe, possibly during the Middle Ages or earlier. They are also known locally in Bavaria as schrazellöcher (German: "scratch holes") and zwerglöcher (German: "dwarf holes"), and in Austria as grufen, while similar structures in France are known as souterrains aménagés (French: "subterranean tunnels").