Experts Baffled by Mysterious Underground Chambers

July 24, 2011— -- There are more than 700 curious tunnel networks in Bavaria, but their purpose remains a mystery. Were they built as graves for the souls of the dead, as ritual spaces or as hideaways from marauding bandits? Archeologists are now exploring the subterranean vaults to unravel their secrets.

Beate Greithanner, a dairy farmer, is barefoot as she walks up the lush meadows of the Doblberg, a mountain in Bavaria set against a backdrop of snow-capped Alpine peaks. She stops and points to a hole in the ground. "This is where the cow was grazing," she says. "Suddenly she fell in, up to her hips."

A crater had opened up beneath the unfortunate cow.

On the day after the bovine mishap, Greithanner's husband Rudi examined the hole. He was curious, so he poked his head inside and craned his neck to peer into the darkness. Could it be a hiding place for some sort of treasure, he wondered? As he climbed into the hole to investigate, it turned out to be a narrow, damp tunnel that led diagonally into the earth, like the bowels of some giant dinosaur.

Suddenly the farmer could no longer hear anything from above. He panicked when he realized that it was getting difficult to breathe the stifling air -- and quickly ended his brief exploration.

The Greithanners, from the town of Glonn near Munich, are the owners of a strange subterranean landmark. A labyrinth of vaults known as an "Erdstall" runs underneath their property. It is at least 25 meters (82 feet) long and likely stems from the Middle Ages. Some believe that it was built as a dwelling for helpful goblins.

The geologists and land surveyors who appeared on Greithanner's property at the end of June were determined to get to the bottom of the mystery. Three members of a group called the "Working Group for Erdstall Research," wearing red protective suits and helmets, dragged the heavy concrete plate away from the entrance and disappeared into the depths.

Their leader, Dieter Ahlborn, began by crawling through a passageway only about 70 centimeters (2 foot 3 inches) high. His colleague Andreas Mittermüller had to return to the surface when the lack of oxygen in the tunnel gave him a headache. Ahlborn continued crawling into the space until his lamp revealed a decayed piece of wood.

He picked it up as if it were a precious stone, knowing that it could offer an important clue about the age of the manmade cave.

Meanwhile, in the meadow above, a group from the State Office of Historic Preservation in Munich had marked off the site with colored tape. Then they rolled a three-wheeled cart equipped with ground-penetrating radar across the grass. "The gallery has collapsed at the back," one member of the group explains. "We're figuring out its actual size."

The exploration of the site is a pioneering activity, marking the first time an archeological agency in Germany is showing an interest in an extremely unusual ancient phenomenon. Similar small underground labyrinths have been found across Europe, from Hungary to Spain, but no one knows why they were built.

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.