Postojna Cave Deep Dive
Postojna Cave in southwestern Slovenia is one of the largest and most-visited show caves in the world — over 41 million visitors since opening in 1819. The 24-km system contains a 3.7-km electric railway, the world's first electric-lit cave, and Europe's most famous cave-fauna species, the olm.
Geological setting
Postojna formed in Cretaceous limestone of the Karst plateau, the type locality for the global term "karst" (from Slovenian "Kras"). The Pivka River sinks into the cave at Postojna Town and flows through it for 24 km before resurging beyond Planina.
Discovery and tourism history
Local people knew of the cave for centuries; graffiti dating to 1213 has been found on cave walls. The system's full extent was revealed by Luka Cec in 1818 — his discovery led to the cave's opening to tourism the following year. Imperial Austrian infrastructure introduced electric lighting in 1884 — three years before the streetlights of Ljubljana — and the railway in 1872.
The olm (Proteus anguinus)
The olm is the flagship species of European cave fauna: blind, pale, externally gilled, capable of living over 100 years and surviving years without food. Postojna has Europe's most accessible olm exhibit at the visitor centre, where visitors see the animals in near-natural conditions.
Tour
The tour begins with the famous railway journey for 3.7 km into the cave; visitors then walk a 1.5-km circuit through the major halls including the Concert Hall (acoustics permit choral performances), the Spaghetti Hall (soda-straw stalactites), and the Pillar of Hercules — a 16-m column on the route. Return is by train.
Practical information
Open year-round; cave constant 10°C. Tours every hour in peak season. Booking recommended in summer. Combination tickets with Predjama Castle and the olm exhibit available.
Explore on the map
See Postojna Cave on the interactive map.