Municipality in Lower Austria, Austria
Hinterbrühl
Hinterbrühl is a town in the district of Mödling in the Austrian state of Lower Austria.
It is home to the Seegrotte, a system of caves including Europe's largest underground lake. During World War II, a satellite camp of Mauthausen concentration camp was opened inside the caverns, producing parts for the He 162 Spatz jet fighter.
Text adapted from Wikipedia, CC BY-SA 4.0. Photograph: Wikimedia Commons (see Commons), Wikimedia Commons.