The Queen of the Underground and World’s Most Famous Cave

Enter the most captivating underground world in Europe. Postojna Cave is a natural wonder on a massive scale, boasting a 24 kilometer network of tunnels, galleries, and majestic halls carved by the Pivka River. It is the only cave in the world with a double-track railway, meaning your journey begins with an unforgettable electric train ride deep into the earth.

But the magic doesn’t stop there. Postojna is the home of the famous ‘Baby Dragons’ (Proteus anguinus)—mysterious aquatic salamanders that live in eternal darkness. Located just 9km from the dramatic Predjama Castle (built into a cliff mouth), this is an essential stop on any Slovenian itinerary. Explore our guide to tickets, tours, and the secrets of this subterranean kingdom.