Underground World of Wonders

Even if you’ve explored Slovenia from one end to another, you certainly haven’t seen everything if you didn’t venture deep into its underground world.  A multi-branch system, not yet fully explored, was carved out by underground rivers and tectonic shifts over the centuries and is considered one of Slovenia’s top attractions. 

Interestingly enough, underground wonders are not found only in the mysterious Karst, but also elsewhere in Slovenia.

Postojna Cave is considered one of the most beautiful, interesting and biologically diverse karst caves in the world. This is the longest tourist cave in Europe and has been open to the public for two hundred years.

One of its unusual aspects is the underground train that takes you along the route of the oldest cave railway in the world. During the train ride, you are taken through magical tunnels, galleries of speleothems and vast majestic underground halls carved out by the Pivka River.

More than 150 animal species live in Postojna Cave, but the best known among them is certainly the olm (Proteus anguinus) which you can see up close in the Vivarium. 

This odd-looking little creature, which reminds some of a baby dragon, is fully adapted to living in complete darkness as its skin contains no protective pigment. Its pale pink skin resembles that of people, which is why it is also called the human fish.

Not far away from Postojna Cave, another Slovenian attraction can be found: the renowned Predjama Castle. The largest cave castle in the world, built into a steep rocky cliff rising 123 metres above the ground, has been reigning over the surrounding area for more than 800 years.

In the 15^th century, the castle was the home of the Slovenian Robin Hood, robber baron Erazem of Predjama. The castle is connected with a cave underneath it by means of hidden underground tunnels.

Did you know that the largest underground canyon in Europe is located in Slovenia? It is 146 metres deep. Other breathtaking sights can also be found in the Škocjan Caves Regional Park, which is part of the UNESCO world cultural and natural heritage protection. 

In the Notranjska region famous for its intermittent Lake Cerknica, Križna Cave can also be found. The cave will stun you with several picturesque underground lakes whose water is of an unusual emerald colour and on which you can paddle in boats.  The remains of a cave bear, which hibernated in the cave during the ice age, have also been found here.