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, is an enormous castle and one of the oldest fortresses in South Eastern Europe. It was built on the top of the extinct volcano vent, overlooking the Ibar river.