Start your tour at Postojna Cave, one of the best-known caves in the world, where the underground landscape can be traversed on an electric train. Meet this underground kingdom’s most famous inhabitant, the Proteus. A fantastic web of tunnels, passages, galleries and halls, and the astonishing diversity of karst features await. Move on to the Predjama Castle. This picturesque and impregnable castle has been perched on a 123-meter 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 below the castle. The only preserved cave castle in Europe, Predjama offers a unique insight into the building techniques of the Middle Ages. During a siege that took place in the 15th century, the castle provided a refuge for its best known and most notorious owner, Erazem of Predjama. Learn about the incredible history of this castle, before you return.