The Most Common and Funniest Questions Asked by Postojna Cave Visitors

2024 marks 200 years of the world’s first cave guiding service, which was established in Postojna Cave, and this seemed like a fitting opportunity to reveal some of the most unusual, funniest and most common questions asked by Postojna Cave visitors.

Stanislav Glažar, a guide with 42 years of experience as a Postojna Cave tour guide, points out, “There are no weird questions. The only thing that can be stupid are the answers.”

1. Is Postojna Cave underground?
Postojna Cave was created as a natural formation typical of the karst world. It is an underground cavern formed through the gradual dissolution of soluble rocks such as limestone. The entire cave is underground and has seven natural entrances, two of which are in the form of shafts.

2. Is Postojna Cave natural or hand-carved? 
Postojna Cave is the eighth wonder of the world and certainly Slovenia’s largest natural attraction and is also protected. It has been shaped over thousands of years by the underground Pivka river and geological processes. In the past, humans set up the cave lighting, railway tracks and tour trails, thus adapting the cave for tourism.

3. Do stalactites and stalagmites ever break off during earthquakes?
If you ask the locals and cavers, Postojna Cave is definitely one of the safest places to be during an earthquake. As it is deep enough below the earth’s surface, it is relatively protected from the direct effects of surface earthquakes. In addition, the geological formations in Postojna Cave are stable and solid, which further reduces the risk.

4. How long is Postojna Cave and how deep does it go?
Postojna Cave is a horizontal cave, which makes it easy to enter by rail. At 24 km long, its appearance varies considerably, as does its depth. In the deepest cave parts, visitors can find themselves up to 115 m underground.

5. Are the cave formations salty?
If you’d like to get an answer to this, make sure not to try it, as you will destroy the cave formation! Believe me: the cave formations in Postojna Cave are not salty. The CO2 escaping from the dripping water leaches out calcite or limestone, which is called speleothems. This limestone is then deposited on the cave walls. The cave formations grow very slowly – only a few centimetres every thousand years.

6. Are there any bats living inside Postojna Cave?
Postojna Cave is the cradle of speleobiology and is home to more than 150 different cave-welling animal species, including bats. However, Postojna Cave is not famous for bats, as they tend to stay in parts of the cave that are away from the main tourist routes. Bats are an important part of the cave ecosystem, which makes maintaining their habitat crucial for the long-term health and ecological balance of Postojna Cave.

7. Can you eat olms?
The olms are endemic to the Dinaric Karst, and their home is the karst ground and Postojna Cave. These mysterious animals are protected by law and classified as an endangered species. All of us are the guardians of olms, which have been nicknamed baby dragons. For this reason, we feel it is important to point out that it is illegal and unethical to eat or use olms for food. We work hard on preserving the population of olms in their natural habitat, as they are an important part of the karst cave ecosystem.

8. Why can’t you see the roots of the trees?
Postojna Cave is deep below the ground, so the roots of the trees on the Earth’s surface, above the cave are not visible in the cave ceiling. In addition, the limestone rocks that form karst caves are usually very hard and solid, making it difficult for roots to penetrate, even when the cave is not that far below the surface.

9. Inside Postojna Cave, is the Pivka river above or below us?
Before visiting the classic Postojna Cave, you can see the Pivka river, which formed this awe-inspiring cave system, in the cave entrance area by the sinkhole, and during your tour in the magnificent hall called the Great Dome. As for the rest, the river is ‘below us’ during most of the tour, at the lowest level, as Postojna Cave is a multi-level cave system.

10. Is there Wi-Fi in Postojna Cave?
Postojna Cave is so interesting and magnificent that there is no need for you to be connected to the social networking sites and other means of communication during the tour. We want you to enjoy the incredible views, watch the world around you and enjoy the peace and quiet. As most of the cave is deep underground, there is limited or no internet access in most parts of the cave.