Postojna Cave is one of the largest and most visited karst cave systems in the world, stretching over 24 kilometers and home to one of the earliest cave railways, opened in the 1870s.
Record no. MRB-2026-006433
Largest Karst Cave System Open to the Public
Reference Record – Not Certified
This record is compiled from publicly available sources for reference. It has not been examined or certified by The Book of World Records.