2 stops in walking order

Castle

The Zrinski-Frankopan family's medieval castle sits on a cliff above the Kupa — an unusually complete complex with an inner keep, a chapel and a modest but interesting museum. The small hydroelectric plant next door, designed in Vienna Secession style in 1908, is a treat for industrial-heritage fans.

~1 h 30 m at this stop

Museum

Munjara Ozalj — Croatia's first purpose-built hydroelectric plant, working since 1908 — sits beneath the medieval Ozalj castle on the Kupa river. The powerhouse is now a hands-on industrial museum with original Ganz turbines still spinning to demonstrate 110-year-old generator technology.

~1 h at this stop