For a trip back in time, head to Hrad Divci Kamen. A huge 600-year-old castle ruin set on a hilltop beside a river, climb up into the ruin to explore the crumbling walls and rooms that are — remarkably — still mostly intact. There usually aren’t too many other people around so you can take in the history of this incredible building at your own leisure. It’s also located right near the Klet mountain making it perfect to combine both as a day trip.
The castle is open all year round, from dawn to dusk.