Founded in 1949 and a member of Swiss Speleological Society. Dedicated to exploration, hydrology, techniques and survey activities of the karst area of the Muotha Valley. Includes history of the Hölloch system, photo gallery and contact information.

Founded in 1979. Coordinates exploration and scientific research, exchanges data and information, and promotes conservation. Includes contacts. [German, French and English].

Encourages exploration and scientific study. Includes UIS calendar of events and contacts. [French, German and some English text].