Predjama Castle is must see visit for castle or old buildings lovers. Inside the castle you can see a lot of things on each of 6 floors. Interesting are some hidden passages and caves behind the castle. On the top floor you can visit also big cave behind the castle. There are also some other special groups to discover caves below the castle. And don't forget also to visit world famous Postojna Cave that is just about 10 kms away from Predjama Castle.