Medieval fortification of Golubac, erected in 14th century, at the entrance of the narrowest gorge at the Danube canyon of Djerdap, named Iron Gate. The fortress was constructed following the relief of the slopes of the Ridan Mountain and was very well protected. Some higher parts of fortification were nearly unreachable. It is one of the most attractive and well preserved fortifications in Serbia, from medieval period. Today you can find the Golubac fortress at the very entrance of national park Djerdap, along right bank of the Danube River.