800 Years of Postojna Cave

A stylised spiral representing the cave, flanked by two stalagmites; the name 'Postojnska Jama' extends along the spiral; the years 1213 and 2013, along with the state name 'Slovenija'.

With over 24 kilometres of explored passages, Postojna Cave is one of the longest show cave systems in Europe. This karst labyrinth formed over millions of years as the Pivka River carved its way through the limestone massif of Inner Carniola. A special biological feature is the olm (Proteus anguinus), a blind, fully aquatic salamander that has lived for decades in the cave's underground river system and is regarded as an emblem of the Slovenian karst landscape. The cave has been scientifically documented since the early 19th century; the first known tourist visit dates to 1819, when Emperor Francis I of Austria visited the site, laying the foundation for the mass tourism that continues to this day.

Postojna Cave lies at the heart of the Slovenian Karst, a landscape that gave international geology the term "karst" itself. The cave system is part of a larger complex that also includes Predjama Castle, a fortress built into a cliff face. Slovenia issued a 2-euro commemorative coin in 2013 to mark the 800th anniversary of the first documented mention of Postojna Cave in 1213. The cave has been under nature protection since 1986 and receives several hundred thousand visitors each year, making it one of the most visited tourist attractions in the territory of the former Yugoslavia.