Zvečan Fortress

The Fortress of Zvečan (Serbian: Tvrđava Zvečan, Тврђава Звечан / Zvešanski grad, Звечански град, Albanian: Kalaja e Zveçanit), also known as Zvečan/Zveçan medieval fortress and Fortress of Mitrovica (Albanian: Kalaja e Mitrovicës), located in the north-west of the city of North Kosovska Mitrovica, in North Kosovo^[a], is an enormous castle and one of the oldest fortresses in South Eastern Europe.^[2] It was built on the top of the extinct volcano vent, overlooking the Ibar river.

• http://en.wikipedia.org/wiki/Zvečan Fortress