Schöner Artikel auf spOnline-International, der am Wochenende an mir vorbeiging, über uralte, hunderte sogar tausend Jahre alte Tunnelsysteme unter Bayern und Österreich, in denen der Legende nach Erdgeister gehaust haben sollen.
At least 700 of these chambers have been found in Bavaria alone, along with about 500 in Austria. In the local vernacular, they have fanciful names such as "Schrazelloch" ("goblin hole") or "Alraunenhöhle" ("mandrake cave"). They were supposedly built by elves, and legend has it that gnomes lived inside. According to some sagas, they were parts of long escape tunnels from castles.
In reality, the tunnels are often only 20 to 50 meters long. The larger passageways are big enough so that people can walk through them in a hunched position, but some tunnels are so small that explorers have to get down on all fours. The tiniest passageways, known as "Schlupfe" ("slips"), are barely 40 centimeters (16 inches) in diameter.
The ground beneath the southern German state of Bavaria is literally perforated with these underground mazes -- and no one knows why.