Belgrade
The first settlements on the city's territory date back to Vinča cutlure. The city itself (under the name Singidunum) was founded by the Celtic Scordis tribe in the 3rd century BC. Then it was owned by the Romans, Byzantines, Avars, Slavs, etc. In 878 it was first mentioned as Belgrade. In 1403 it became the Serbian capital. In 1521, the city was conquered by the troops of the Ottoman Empire. In 1815 it again became the capital of Serbia. From 1918 to 2003 it was the capital of Yugoslavia. In 2003-2006, Belgrade was the unofficial capital of the confederal union of the two states of Serbia and Montenegro.