Postojna Cave
Postojnska jama
One of Europe’s most famous karst caves. Ride a little train deep underground to see the great hall of stalactites and the “baby mermaid” olm.
Postojna Cave lies about 50 km southwest of Ljubljana, in a karst region (the word “karst” itself derives from this part of Slovenia). It is a cave system carved by the Pivka River, with more than 24 km of explored passages, making it Slovenia’s longest cave. It opened to visitors in 1819, and in 1872 a track was laid inside, making it the world’s first cave tourist railway. The visit takes about 1.5 hours. First you ride a double-track little train underground for about 3.7 km. Then, with a guide, you walk about 1.5 km through areas such as the “Big Mountain,” the “Beautiful Cave,” and the “Italian Hall,” passing many stalactites, stalagmites, and columns. The highlight is the snow-white “Brilliant” stalagmite, about 5 m tall, which is the symbol of the cave. Finally, you take the train back from the Concert Hall, which can hold about 10,000 people. The cave is home to the olm (Proteus), a blind, pinkish-white amphibian that can live for a hundred years. Locals call it the “baby mermaid,” and you can view them in aquariums. Admission is about 35–45 euros. There is a combined ticket with Predjama Castle, a medieval castle built into a cave mouth on a 123 m cliff about 9 km away (check the official website). The cave stays at a constant temperature of about 10°C, so bring a jacket. From Ljubljana, the trip takes about 1 hour by train or bus.
Opening hours
Open year-round with multiple daily tours (summer approx. 09:00–17:00, hourly; fewer sessions in winter; check official website)
Nearby sights
- Predjama Castle
- Plečnik House
- Škofja Loka
- Tivoli Park
- Križanke
- National and University Library of Slovenia
- National Museum of Slovenia
- National Gallery of Slovenia