Goldbacher Stollen, Underground tunnel system in Überlingen, Germany.

Goldbacher Stollen is a tunnel system driven into Molasse rock between Goldbach and Überlingen on the northern shore of Lake Überlingen. By the end of the war it comprised 17 cross tunnels and eight entrances with a total length of over four kilometres; passage widths vary from two to 25 metres and heights from two to ten metres, and some junctions were built out in hall form.

Between June 1944 and April 1945, prisoners from a concentration camp constructed these passages to relocate military production from Friedrichshafen during World War II. The construction work ceased as the war came to an end.

The site is named after the Goldbach district between Goldbach and Überlingen. A Slovenian prisoner, Boris Kobe, drew tarot cards shortly after the war depicting prisoners beaten on the march to work, bitten by dogs, buried by falling rock, operating pneumatic drills and pushing a tip wagon by hand.

The tunnel maintains a constant temperature of around 12 degrees Celsius throughout the year, so visitors should bring warmer clothing. It is best to arrange a guided tour in advance with local operators.

The prisoners' route from the Aufkirch subcamp to the tunnel was about 1.5 kilometres. The Slovenian prisoner Boris Kobe drew tarot cards shortly after the war depicting the labour: men driven to work and bitten by dogs, workers buried by falling rock, work with the pneumatic hammer and a hand-pushed tipping wagon.