Imagine boarding a train not to another city, but to the heart of the Earth. In Slovenia, Postojna Cave offers just that—a journey into a breathtaking subterranean world of geological wonders, storied history, and myths that come to life.
An Adventure That Begins by Rail
A visit to Postojna
Cave is unlike any other caving experience, primarily because it begins on the world's first and only double-track cave railway. For over 140 years, this train has been whisking visitors deep into the mountain. The 3.7-kilometre ride is an adventure in itself, as the open-air carriages glide through artificially lit tunnels and into the first of many grand caverns, revealing a hidden landscape sculpted over millions of years by the Pivka River. The railway, first opened in 1872 when guides pushed the carts by hand, was electrified in 1945 and remains the thrilling first chapter of any tour.
A Gallery of Natural Sculptures
Once off the train, a guided 1.5-kilometre walk begins on a well-maintained path through a mesmerizing gallery of natural art. The cave is a masterclass in geology, filled with countless stalactites hanging like icicles and stalagmites rising from the floor. You'll pass through halls with distinct characteristics, like the Red Hall, coloured by iron minerals, and the White Hall, where pure calcite creates snow-white formations. A highlight is the Spaghetti Hall, with its ceiling covered in delicate, hollow stalactites. The undisputed star of the show is 'Brilliant', a five-metre-tall, dazzling white stalagmite that has become the symbol of the cave. Nearby stands a pillar-like formation, blackened from a fire set by partisans to destroy an occupying army's fuel stores during WWII.
Meet the Legendary 'Baby Dragons'
Postojna is not just a geological marvel; it's a cradle of speleobiology. The cave is home to the olm (Proteus anguinus), a blind aquatic salamander that ancient locals believed were baby dragons washed out from a dragon's lair deep within the Earth. These pale, serpent-like creatures are perfectly adapted to the eternal darkness. They can live for up to 100 years and survive without food for several years. While spotting them in the wild is nearly impossible, the tour includes a visit to a large aquarium where you can observe these fascinating endemic animals. The successful hatching of 22 olms in 2016 was a globally celebrated event, cementing the cave's role in the conservation of this unique species.
The Grandeur of the Concert Hall
The tour culminates in the Concert Hall, an immense cavern with astounding natural acoustics where a sound can echo for up to six seconds. This subterranean amphitheater is so vast it can hold up to 10,000 people and has hosted performances by symphony orchestras and various solo artists over the years. Looking up, you might see magnificent Murano glass chandeliers, which add to the hall's fairytale atmosphere. This chamber also contains the world's oldest underground post office, where you can mail a postcard from deep within the Earth. It serves as a breathtaking final stop before you board the train for the return journey to the surface.
Planning Your Underground Journey
A tour of Postojna Cave takes about 90 minutes. The temperature inside is a constant 10°C yearround, so dressing in warm layers and wearing comfortable sports shoes is highly recommended, as the walking path can be slick and includes some slopes. The cave is accessible for visitors of all ages, including families with young children, and guided tours are available in several languages. For a full day of adventure, many visitors combine their cave tour with a trip to the nearby Predjama Castle, a stunning medieval fortress built into the mouth of a cliff just a few kilometres away.
