Brussels (French: Bruxelles, [bʁysɛl] ( listen); Dutch: Brussel, [ˈbrʏsəɫ] ( listen)), officially the Brussels Region or Brussels-Capital Region (French: Région de Bruxelles-Capitale, [ʁe'ʒjɔ̃ də bʁy'sɛlkapi'tal] ( listen), Dutch: Brussels Hoofdstedelijk Gewest, [ˈbrʏsəɫs ɦoːft'steːdələk xəʋɛst] ( listen)), is the capital of Belgium and the de facto capital of the European Union (EU). It is also the largest urban area in Belgium, comprising 19 municipalities, including the municipality of the City of Brussels, which is the de jure capital of Belgium, in addition to the seat of the French Community of Belgium and of the Flemish Community.

Brussels has grown from a 10th-century fortress town founded by a descendant of Charlemagne to a sizeable city. The city has a population of 1.1 million and a metropolitan area with a population of over 1.8 million, both of them the largest in Belgium. Since the end of the Second World War, Brussels has been a main centre for international politics. Hosting principal EU institutions and the headquarters of the North Atlantic Treaty Organization (NATO), the city has become the polyglot home of numerous international organisations, politicians, diplomats and civil servants.