Visit Postojna Cave, the best-known cave in the world, and the Predjama Castle, the only preserved cave castle in Europe. Postojna Cave, the queen of all caves, is the best-known cave in the world. It is also the greatest tourist attraction in Slovenia and one of the world’s largest karst monuments. This is the only place in the world where the underground landscape can be traversed on an electric train and where you get to meet this underground kingdom’s most famous inhabitant – the proteus (olm) – up close. A fantastic web of tunnels, passages, galleries and halls, astonishing diversity of karst features, as well as easy access are certainly the main reasons for such popularity of the cave and a large number of visitors (more than 36 million of them in over 200 years). The Predjama Castle reigns over the surrounding area, not far from the Postojna Cave, in the idyllic village of Predjama. This picturesque, magnificent, defiant, mysterious and impregnable castle has been perched up in the middle of a vertical 123m high cliff for more than 800 years. Its romantic appeal is further emphasized by the idyllic Lokva River, which disappears into the underground world deep down below the castle. As the only preserved cave castle in Europe, the Predjama Castle offers a unique insight into the building techniques and resourcefulness of people in the Middle Ages, who were looking for and found a safe harbor for themselves right at the entrance into the cave. During a siege that took place in the 15thC, the castle provided a refuge for its best known and most notorious owner - Erazem of Predjama. The legend about the courageous robber baron Erazem, who remained undefeated until one of his servants betrayed him, is still in people’s minds, inspiring and alluring as ever. It was this safe abode of his which helped the brave knight resist the besiegers without much difficulty for more than a year.