Ostrožac is one of BiH's most photogenic castles, a spooky Gothic place high above the Una Valley and accessed from the Cazin road, 4km of hairpins above the Una. The central garden has been a sculpture garden since 1969 but the interior of the buildings remains in a pretty ruinous state. To get in you may need to call the caretaker.
First mentioned in 1286 Ostrožac, the castle capitulated to Turkish forces in 1577, was swiftly regained then lost again by 1579. It was the seat of local captains for 250 years and was restored with its current very Gothic look around 1905.