Grad Kalec is a romantic castle ruin hidden among old lime trees near the village of Knežak, close to the source of the Pivka River. Of the once-grand castle, immortalized in Valvasor's famous work on the Duchy of Carniola, only the tower remains — yet it gives the site a striking, slightly melancholic atmosphere.

The ruins sit on the slope of Breg hill (618 m), reached by a chestnut-lined avenue that makes for an especially atmospheric walk in autumn. This is a place where quiet nature meets centuries of history — the castle changed hands many times, hosted a mass rally for a United Slovenia in 1869, and served as a secret meeting place for TIGR resistance activists during World War II.

• Knežak — easy to moderate walk along the chestnut avenue
• The Krpanova pohodniška pot trail passes directly by the ruins

• Surviving tower and castle ruins surrounded by old lime trees
• Historically linked to the family of composer Miroslav Vilhar, who died here

It's worth knowing that in 1869, on Vilhar's initiative, a great patriotic gathering took place here — a landmark event in Slovenian national history.