Golubac Fortress (Golubački grad) was a medieval fortified town on the south side of the Danube River, 4 kilometers downstream from the modern-day town of Golubac, Serbia. The fortress, which was most likely built during the 14th century, is split into three compounds which were built in stages. It has ten towers, most of which started square, and several of which received many-sided reinforcements with the advent of firearms.

Golubac Fortress has had a tumultuous history. Prior to its construction it was the site of a Roman settlement. During the Middle Ages, it became the object of many battles, especially between the Ottoman Empire and the Kingdom of Hungary. It changed hands repeatedly, passing between Turks, Bulgarians, Hungarians, Serbs, and Austrians, until 1867, when it was turned over to the Serbian Knez, Mihailo Obrenović III. Now, it is a popular tourist attraction in the region and a sightseeing point on Danube boat tours.

(Source: historyofyugoslavs)