Postojna Cave - the queen of all caves - is the most famous cave in the world and Slovenia’s top natural attraction. It is one of the largest karst monuments on the planet and the only cave where you can explore the underground world by electric train. Discover a spectacular network of tunnels, passages and vast halls shaped over millions of years, and meet its most iconic resident - the mysterious proteus (olm). With its remarkable karst formations and easy accessibility, it has captivated more than 36 million visitors over the past 200 years.

Perched dramatically within a 123-meter-high vertical cliff near Postojna Cave, Predjama Castle dominates the idyllic village of Predjama. For more than 800 years, this magnificent and mysterious fortress has stood at the entrance of a vast cave system, blending natural rock and medieval architecture into a truly unique sight. The romantic setting is enhanced by the Lokva River, which disappears underground beneath the castle. As the only preserved cave castle in Europe, Predjama offers a fascinating insight into medieval ingenuity and building techniques. In the 15th century, the castle became the refuge of its most famous owner, Erazem of Predjama - a legendary and rebellious knight who resisted a lengthy siege thanks to a secret passage through the cave. His dramatic storey of bravery and betrayal still captures the imagination today.