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Seegrotte: Journey to the Center of the Earth

4.4 (1041)

Explore Europe's largest underground lake in a former gypsum mine with a fascinating and dark WWII history, just a short trip from Vienna.

Descend into the Seegrotte, a former gypsum mine near Vienna, and explore Europe's largest underground lake. A boat trip through the flooded caverns reveals a unique blend of natural wonder and WWII history, where parts for the Heinkel jet fighter were once produced by forced laborers.

A brief summary to Seegrotte

  • Monday 9:30 am-4:30 pm
  • Tuesday 9:30 am-4:30 pm
  • Wednesday 9:30 am-4:30 pm
  • Thursday 9:30 am-4:30 pm
  • Friday 9:30 am-4:30 pm
  • Saturday 9:30 am-4:30 pm
  • Sunday 9:30 am-4:30 pm

Local tips

  • Wear warm clothing and sturdy shoes, as the temperature inside the Seegrotte is a constant 9°C (48°F) and the tour involves walking and descending stairs.
  • Photography is allowed for private purposes, but flash photography may be restricted to protect the cave environment.
  • Consider visiting during the warmer months (April to October) for more favorable weather, though the cave maintains a constant temperature year-round.
  • Allow approximately 50 minutes for the guided tour and boat ride.
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Getting There

  • Public Transport

    From Vienna, take a train to Mödling Bahnhof. From there, take bus line 364 to Hinterbrühl. Get off at a stop in Hinterbrühl, from which it is a short walk to Grutschgasse 2a. A single bus fare from Mödling is approximately €3-4. The total journey from Vienna takes approximately 1-1.5 hours.

  • Car

    From Vienna, drive south on the A21 motorway towards Hinterbrühl. Take the Hinterbrühl exit and follow the signs to Seegrotte. Parking is available near the Seegrotte, though it may be limited. Parking is free.

Discover more about Seegrotte

The Seegrotte, located in Hinterbrühl, just south of Vienna, offers a unique subterranean adventure. Originally a gypsum mine dating back to the 19th century, a blasting accident in 1912 unleashed a torrent of water, creating a vast underground lake. Abandoned for nearly two decades, the grotto was rediscovered in the 1930s and transformed into a tourist attraction.A guided tour takes you deep into the earth, 60 meters below the surface, through a labyrinth of tunnels and past remnants of the mining operations. The highlight is the boat ride on the emerald-green lake, which stretches over 6,200 square meters. The still, cold waters reflect the cave's formations, creating a mystical atmosphere.The Seegrotte also holds a darker chapter in its history. During World War II, the Nazis converted the upper levels of the mine into an underground aircraft factory. Forced laborers from a sub-camp of the Mauthausen concentration camp were forced to produce parts for the Heinkel He 162 Salamander jet fighter, a desperate attempt by the Third Reich to regain air superiority. Today, an exhibition within the grotto sheds light on this period, serving as a reminder of the horrors of war.After the war, the Seegrotte was returned to its function as a tourist attraction. The blend of natural beauty and historical significance makes it a compelling destination. The constant temperature of 9°C (48°F) makes it a cool escape on a hot day, but warm clothing is recommended.
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