Angerlloch, Waterfall and cave system in Wallgau, Germany

Angerlloch is a karst cave on the eastern slope of the Simetsberg in the Estergebirge, about 890 metres above sea level near Wallgau. It has two entrances roughly 10 metres apart and 1,469 metres of surveyed passages with a height difference of about 40 metres. An active stream runs through the cave, passing siphons, a waterfall, sinter pools and several lakes, with galleries following two intersecting joint directions on two levels.

Because the Angerlloch lies close to the valley, it has been known for a long time and is well explored. The Bavarian State Office for the Environment lists it as a valuable geotope under the number 180H001. Its two entrances can be closed with steel grilles, and from 1 October to 30 April the cave may not be entered because bats overwinter inside.

The cave is used for cave rescue exercises and guided tours for youth groups, and its proximity to the valley has made it a popular training ground for cavers. The lower entrance often floods during snowmelt, so visits are timed accordingly.

The cave lies on the east slope of the Simetsberg at about 890 m, reachable from Wallgau; both entrances can be closed with steel grilles. Entry is forbidden from 1 October to 30 April each year by order of the nature conservation authority to protect hibernating bats. Only experienced cavers with mountain boots, climbing harness, rope, oversuit, helmet and headlamp with spare batteries should enter; the lower entrance is often flooded during snowmelt and after heavy rain.

The Volksbad siphon takes its name from the steep, slippery walls that must be climbed to bypass it, a manoeuvre that often fails spectacularly. Beyond this bypass, researchers once signed the cave register at the Kristallsiphon. Reaching the deepest section requires wading the 25-metre Kristallsiphon, climbing a 5-metre clay wall and descending a 7-metre shaft above the Eisensee.