The Riesending Cave is the longest and deepest known cave system in Germany, stretching 27.3 kilometers in surveyed length and plunging 1,149 meters into the depths of the Untersberg massif. It's a place legendary among cavers, made famous worldwide by a dramatic ten-day rescue operation in 2014.

Carved through limestone in the Berchtesgaden Alps, the cave is considered a textbook example of alpine karst formation. Right after the entrance on the Untersberg plateau, at 1,843 meters above sea level, a series of vertical shafts drops 450 meters straight down. Deeper inside, an underground stream flows through narrow canyon passages, feeding waterfalls and a 30-meter lake that can only be crossed by inflatable boat. Temperatures stay between 1.5°C and 5°C year-round with nearly 100% humidity, and the entire system is prone to sudden flooding during snowmelt and storms.

How to get there

• Located on the Untersberg plateau in the municipality of Bischofswiesen, Bavaria — access is strictly restricted and requires special permission

Practical information

• Since 2014 the entrance has been sealed with a steel grate and lockable hatch
• Entry is granted only by the municipality of Bischofswiesen for justified research purposes, subject to physical and technical fitness requirements
• Recognized by the Bavarian Environment Agency as an especially valuable geotope
• Exploration requires technical rope climbing and multi-day underground bivouacs

The cave's name comes from the astonished exclamation of its discoverers: 'That's a real riesending (huge thing)!' In 2014 it gained international attention after a caver was seriously injured 950 meters underground, triggering one of the most complex cave rescues in history.