The Hölloch is a 200.4 km long cave in the municipality Muotathal in Switzerland. In addition to being the second longest cave in Europe, it is also notable for having a depth of 938.6 m. The Hölloch is an example of a karst cave system.
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Address Hölloch, 6436 Muotathal, Switzerland
Coordinates 46°58'37.029" N 8°47'19.303" E