Brussels (French: Bruxelles, ; Dutch: Brussel, ), officially the Brussels Region or Brussels-Capital Region (French: Région de Bruxelles-Capitale, Dutch: Brussels Hoofdstedelijk Gewest), 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 more than one million inhabitants. The city has a population of 1.1 million and the metropolitan area has a population of over 1.8 million, both making it 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 as well as 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.
Brussels is officially bilingual, with both French and Dutch being spoken in the city. All road signs, street names, and many adverts and services are shown in both languages. Linguistic tensions remain, and the language laws regarding some municipalities surrounding Brussels are an issue of considerable controversy in Belgium.