Brasília (AFI: [bɾaziljɐ]) is the federal capital of Brazil and the seat of government of the Federal District. The capital is located in the Center-West region of the country, along the geographical region known as Central Plateau. According to estimates by the Brazilian Institute of Geography and Statistics (IBGE) for 2018, its population was 2 974 703 inhabitants (4 284 676 in its metropolitan area), being then the third most populous city in the country. Brasília is also the fifth most populous urban concentration in Brazil. The Brazilian capital is the largest city in the world built in the twentieth century.
The city has the largest gross domestic product per capita in relation to capitals, the fourth largest among the main cities in Latin America and about three times higher than the average Brazilian income. As a national capital, Brasília houses the headquarters of the three branches of the Republic (Executive, Legislative and Judiciary) and 127 foreign embassies. The planning policy of the city, such as the location of residential buildings in large urban areas, the construction of the city through huge avenues and its division into sectors, has provoked debates about the lifestyle of large cities in the twentieth century. The city's project divides it into numbered blocks, as well as sectors for predetermined activities, such as the Hotel, Banking and Embassies Sector.
The urban plan of the capital, known as the "Pilot Plan", was prepared by the urbanist Lúcio Costa, who, taking advantage of the relief of the region, adapted it to the project of Lake Paranoá, conceived in 1893 by the Mission Cruls. The city began to be planned and developed in 1956 by Lúcio Costa and the architect Oscar Niemeyer, with structural calculations of the engineer Joaquim Cardozo. Inaugurated on April 21, 1960, by then-President Juscelino Kubitschek, Brasília became formally the third capital of Brazil, after Salvador and Rio de Janeiro. Viewed from above, the main area of the city resembles the shape of an airplane, but was designed in a butterfly format. The city, commonly referred to as the "Federal Capital" or "BSB", is considered a World Heritage Site by UNESCO due to its architectural and urban development and has the largest land area in the world, with 112.5 square kilometers.
The city has a unique status in Brazil, since it is a distinct administrative division of a legal municipality, like other Brazilian cities, similar to what happens with Washington, D.C., in the United States, and with Canberra, Australia.
The word "Brasília" is used as a synonym for Distrito Federal as a whole by means of synecdoche; however, the Federal District is composed of 31 administrative regions, of which only one is the center of the entity: Administrative Region I, which is basically formed by the Pilot Plan and the National Park of Brasilia. Demographic publications generally do not make this distinction and list the Brazilian population as synonymous with the population of the Federal District, considering the whole as a single entity. The Federal District accumulates characteristics of state and municipality, and its other administrative regions, also called satellite cities, are not treated as municipalities.