The Fortress of Herzog Stjepan Vukčić Kosača is located in the western part of Herzegovina; It was one of the main fortifications in the area, and the name Herzegovina comes from Duke Stjepan Vukčić Kosača who called himself (Herzog) meaning "governor", and later when the Ottomans invaded Bosnia the fort was repaired and remained in service until year 1835; Nowadays, it is considered one of the wonderful archaeological sites, and it is a must visit.