The Karstic world is a veritable paradise for cave lovers. Postojna Cave and other caves in the same cave system are among the best known in Slovenia. Cross Cave, a visitors’ favourite, stands out in the bevy of Karstic beauties, followed closely by Zelše Caves, Planina Cave, Pivka Cave, and others. You can tour the caves individually or in groups. Most caves have designated touring schedules, and require large groups to book in advance.