Golubac (castle) built
1335 CE.
Shown on the map at 44.661°, 21.678°.
The Golubac Fortress (Serbian: Голубачки град or Golubački grad) was a medieval fortified town on the south side of the Danube River, 4 km (2.5 mi) downstream from the modern-day town of Golubac, Serbia and 2 km (1.2 mi) across the Danube from the village of Coronini, Romania. According to recent discoveries, the fortress, which was built during the 14th century by Medieval Serbian state, 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. Towers were not connected for easier defense. Serbian Medieval frescos were recently found inside the fortress. 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.
Text from the Wikipedia article Golubac Fortress, licensed CC BY-SA 4.0.