Škocjan Caves, Cave system in Divača, Slovenia.

The underground system stretches 3.9 miles (6.2 kilometers) through limestone formations and encompasses several interconnected chambers featuring stalactites, stalagmites and flowstone curtains, while the Reka River flows through deep gorges within the cave, creating waterfalls and natural bridges in the rock structure.

The first written record of the caves comes from Posidonius of Apamea in the 2nd century BC, and they appear on the Lazius-Ortelius map of 1561. In 1689 Johann Weikhard von Valvasor described the sink of the Reka River. Systematic exploration began with a speleology expedition in 1884; explorers reached the banks of Dead Lake in 1890, and in 1904 local men climbed the sixty-metre wall of Müller Hall to discover Silent Cave. The caves were inscribed on the UNESCO World Heritage list in 1986.

The caves take their name from the village of Škocjan on the plateau above the Reka sink. In Fly Cave (Mušja jama), finds show Greek influence, and from the Bronze Age into the Iron Age a cave temple made the gorge a pilgrimage site tied to ancestral worship. Guided tours are given in Slovenian, English, Italian and German.

Reservations are recommended as daily visitor numbers are limited. Tours last approximately 90 minutes and involve walking on paved paths with over 500 steps. Temperature remains constant at 12 degrees Celsius (54 degrees Fahrenheit) year round, so warm clothing is advised. The entrance sits 1.9 miles (3 kilometers) from Divača train station, with bus connections available during summer months.

The Cerkvenik waterfall inside drops 39 feet (12 meters) through an opening in the ceiling and marks the only permanently surface section of the river within the karst system. A colony of more than 250 lesser horseshoe bats hibernates in the chambers, protected by special management protocols during winter dormancy periods.