The fortress Gradina is located in Drnis, at an elevation of 344 m above sea level, above the canyon of the river Cikola. Built on the site of strategic importance, offers a breathtaking view of the city and mountain Promina, spreads at Peter's field and back into the deep rocky canyon Cikola. It is assumed that it was part of the system of fortresses of the noble family Nelipic. During the rule of the Ottoman Empire Gradina was rebuilt for defensive purposes.
With the arrival of the Venetians, in the late 17th century, its demolition was ordered. However, It was restored soon because of the threat of Turkish breaking in, which was present until 1715. god. In the 19th century fortress has lost all function and become a source of building materials for the growing city Drnis. Today remains visible on the southern side are part of the medieval fortress, while the central tower and the north-eastern defense wall are from the period of Ottoman rule. Gradina is registered as a historical monument.