Postojna Cave is a stunning karst cave system located in Slovenia. It stretches over 24,120 meters and features impressive stalactites, stalagmites, and unique rock formations. The cave is famous for its diverse ecosystem, including the rare olm, a blind amphibian that thrives in the dark. Visitors can explore the cave through a guided tour that includes a train ride and walking paths. The temperature inside remains cool year-round, averaging around 10°C (50°F). Postojna Cave is one of the most visited tourist attractions in Slovenia, drawing millions of visitors each year.