Buenos Aires is the capital and largest city of Argentina. The city is located on the western shore of the estuary of the Río de la Plata, on the South American continent's southeastern coast. "Buenos Aires" can be translated as "fair winds" or "good airs", but the former was the meaning intended by the founders in the 16th century, by the use of the original name "Real de Nuestra Señora Santa María del Buen Ayre", named after the Madonna of Bonaria in Sardinia. The Greater Buenos Aires conurbation, which also includes several Buenos Aires Province districts, constitutes the fourth-most populous metropolitan area in the Americas, with a population of around 15.6 million.
The city of Buenos Aires is neither part of Buenos Aires Province nor the Province's capital; rather, it is an autonomous district. In 1880, after decades of political infighting, Buenos Aires was federalized and removed from Buenos Aires Province. The city limits were enlarged to include the towns of Belgrano and Flores; both are now neighborhoods of the city. The 1994 constitutional amendment granted the city autonomy, hence its formal name of Autonomous City of Buenos Aires.