Predjama Castle

13th-century cave castle built into a rock face with restored living quarters, dungeons and secret tunnel.

A fantastic very interesting castle. Audio guides available in many languages. I got so many impressions, it was just wonderful. As a visitor, you can go almost all the way to the top of the castle. Not cheap but definitely worth it.

Lueg cave castle (Predjamski Grad). Fantastic. A castle built into or attached to a cave system. This is indescribably fascinating.
This is connected with stories cf. Robin Hood, but they actually happened. For example, year-long siege, supply through the cave passages, etc.
You can tour the castle yourself using an audio guide. And that works perfectly. Really interesting information. Not too short, not too long, suitable for every age group.

Recommendation. Do, do, do.

Tip. Book the tour through the caves at the castle as well as the Postojna Caves (Postojnska jama), which are only 7 km away.