Quackenschloss Cave, Passage cave in Wiesenttal, Germany.

Quackenschloss is a passage cave about 18 metres long near Engelhardsberg in Wiesenttal, the remnant of a very old, high-lying cave system. Its slanted-oval form follows two longitudinal fissures and two inclined bedding joints, and two larger fissures cross the passage. One portal is roughly 7 metres wide and 2.50 metres high; the other, split by a rock pillar, is about 9 metres wide and 5 metres high. The wall looks perforated because individual shells have weathered out of the Rauchwacke rock, called Quacke locally.

The cave was carved over millions of years as water passed through porous rock layers, slowly opening passages. This natural erosion process created the two openings that exist today.

The name likely comes from the porous, shelled rock: locals call this weathered Rauchwacke "Quacke", and the perforated wall gave the cave its name. Visitors can still see the pitted, gap-riddled rock face beside the entrances. The cave is registered as C 4 in the Franconian Alb cave register and is a designated geotope and natural monument.

The cave is reached via marked hiking paths that vary in length and difficulty from the starting town. You can choose a short walk or combine it with a longer route depending on your time and fitness level.

The two entrances formed along natural rock fractures that merge into a single passage, creating a rare geological layout. This arrangement lets you enter on one side and exit on the other, making it feel like walking through the mountain.