Seegrotte Hinterbrühl
Former gypsum mine in Hinterbrühl with boat ride on Europe's largest underground lake, viewable only on guided tours.
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About the museum
From 1848 onwards, gypsum was mined in Hinterbrühl, initially serving mainly as fertilizer. Over decades, an extensive tunnel system developed on several levels. In 1912, an explosion triggered a massive water inrush: over 20,000 cubic meters of water flooded the lower mining areas, and mining had to be stopped.
Entrepreneur Friedrich Fischer acquired the defunct mine in 1918, had it converted and electrified, and opened it in 1932 as a show mine. Since then, the roughly 6,200 square meter lake, averaging just over a meter deep, has attracted visitors – it is considered Europe's largest underground lake.
During the Nazi period, the Heinkel Works confiscated the tunnels in 1944 and had parts of the jet fighter He 162 manufactured there under the code name 'Languste'. Prisoners from an external camp of Mauthausen concentration camp had to do the work; at the end of the war many of them were murdered or died on the death march to Mauthausen.
In 1993, the grotto served as a filming location for the Disney film 'The Three Musketeers'; a prop boat still reminds of it. After an official closure in 2019, a new operator team took over the show mine, renovated and expanded it. Today tours lead through the tunnels down to the lake, which is traversed by boat.
Highlights
- Boat ride on Europe's largest underground lake
- Tunnel labyrinth of the former gypsum mine
- Traces of underground aircraft production in World War II
- Dragon boat from the film 'The Three Musketeers'
- Tours in numerous languages
- Founded
- 1932
- Operated by
- K & K Bergbau GmbH
Admission & discounts
| Adults | €18 |
|---|---|
| Reduced | €15Seniors 60+, soldiers, apprentices |
| Children & teens | €12Children's and student ticket for 5- to 14-year-olds 12 €. |
| Seniors | €15From 60 years old |
| Students & apprentices | –Students and pupils up to 14 years pay the children's rate; no separate student rate mentioned. |
| Groups (20+ people) | €16 per personAdult groups from 20 people; children's and student groups from 20 people 10 € per person. Advance registration requested. |
| Families | €422 adults and 1 child |
Seegrotte is not a partner of Lower Austria CARD.
Accessibility
- Wheelchair accessible: no information
- Elevator: no information
- Accessible restroom: no information
- Accessible parking: no information
- Service dogs welcome: no information
- Tactile models & exhibits: no information
- Sign language tours: no information
- Easy-to-read materials: no information
- Audio description: no information
The tour and descent of stairs to the lake mean light physical strain. For people with claustrophobia, the visit can be uncomfortable.
Kids & families
| Family ticket | €42 · 2 adults and 1 child |
|---|
Children under 14 may only participate with an adult. Family ticket for 2 adults and 1 child.
Getting there & parking
By public transit
By train to Mödling, then by bus 364 to Hinterbrühl.
By car
Parking available · 5-min walk to the entrance
Public parking nearby, about 5 minutes walk. There is a separate parking lane for tour buses.
Amenities & dining
- Café
- Restaurant: not available
Small espresso next to the cashier building to pass the time.
Events & venue rental
The museum hasn’t published any information on this.
Plan your visit
| Guided tours | yes · approx. 50 min |
|---|---|
| Audio guide | no |
| Photography | Photography and filming for private purposes allowed; commercial or scientific recordings only with permission. |
| Good to know | Visit only on tour including boat ride, without registration; groups of 20+ people register. Tours in many languages possible, such as English, Hungarian, Czech, Hebrew, Dutch, Turkish, Swedish, Italian, French, Russian and Polish. The mine is only 9°C year-round – warm clothes and sturdy shoes (no sandals or flip-flops) are necessary. Animals may not be taken with you. |
