Seegrotte Hinterbrühl, a lake under the earth

Only about 20 minutes from Vienna is one of the most unusual excursion places around the city. In the 19th century, plaster was mined in Hinterbrühl until the miners encountered water in 1912. The tunnels were full, and a lake deep in the mountain emerged, which today is considered the largest underground lake in Europe.

During the guided tour it goes down through the old tunnels to the shore and then with the boat out onto the quiet water. On the way, you will also experience the dark side of the place. During the Second World War, a secret aircraft production of the Wehrmacht was housed in the tunnels. All year round it has only about 9 degrees, so a warm jacket is also mandatory in summer.