Gradac Castle was first mentioned in written documents in 1228. The castle island is mostly covered by a large Renaissance park that is neglected and overgrown. It includes a garden, remnants of an alley, and the mausoleum of the last owner (named Gusič), who was a businessman from Zagreb. There are plans to restore the castle and renew the park. The Municipality of Metlika repaired the roof of the castle to prevent further decay at end of the 1990s.
References:Duino Castle was built by the Wallsee family in 1389 on the cliffs overlooking the Gulf of Trieste. It replaced an older castle from the 11th century. Over time, the Wallsee family disappeared and the castle, after having been used as a prison, became the residence of the Luogar and Hofer.
At the end of the 19th century it became the property of Prince Alexander von Thurn und Taxis from the Czech branch of the House of Thurn and Taxis. It remains with the family to this day with his great-grandson Prince Carlo Alessandro della Torre e Tasso, Duke of Castel Duino the current owner. The castle has been opened to the public as a museum and park.