This is a tour not to be missed! We have visited Carlsbad Caverns here in the United States, and it pales next to Postojna Cave! Words to describe it would fail. The tour takes around 90 minutes and consists of a train ride in and out and then walking around the cave with a guide. It's quite chilly in the cave, so make certain you have adequate clothing. The cave does supply jackets for those who need one. The formations are amazing, and the cave is huge. Definitely not to be missed.
The castle is very interesting and also worth seeing. We were on a cruise, and the tour offered by the cruise line did not include an interior tour of the castle. This tour included everything and was for half the price!
The entire area is beautiful! We loved this visit!