[1] They have long been famous for their countless colorful mineral formations (speleothems) formed over many years by water dripping through relatively soft rock.

The third chamber contains the famed "Fairy Kingdom" (Märchendom), featuring a variegated grouping of deposits that, illuminated by theatrical lights and reflected in a perfectly still pool of water, is thought to resemble miniature castles and other buildings.

Historically, alum was employed in a range of medicinal products, as a food preservative, to clarify water and to finish cloth.

But in 1910 the old mine was rediscovered and explorers took note of the fantastic mineral deposits that had accumulated over the geologically short period of three centuries.

In 1913 the third chamber with the "Fairy Kingdom" was discovered, and shortly before the outbreak of World War I in 1914 tours began to be offered to the public.