Time Out says
Follow the Karlovac star
The original fortress of Karlovac constructed in 1579 may now only consist of a few remnants but you can still follow the line of the defensive moats created by the Habsburgs to keep out the Ottomans. Today these are lovely promenades of chestnut and linden trees, with extensive parkland stretching beyond. Within the borders are clustered many historic attractions and landmarks, centrepieced by the Catholic Holy Trinity Church and Orthodox St Nicholas, around the main square of Trg bana Josipa Jelačića. Perhaps the most prominent spots to observe the 440-year-old fortifications is right outside the Karlovac City Museum, in the north-west corner of the historic hub.