Buenos Aires

Buenos Aires, officially the Autonomous City of Buenos Aires, is the capital and largest city of Argentina. It is located on the southwest of the Río de la Plata. Buenos Aires is classified as an Alpha− global city, according to the GaWC 2024 ranking. The city proper has a population of 3.1 million and its urban area has a population of 16.7 million, making it the twentieth largest metropolitan area in the world.

It is known for its preserved eclectic European architecture and rich cultural life. It is a multicultural city that is home to multiple ethnic and religious groups, contributing to its culture as well as to the dialect spoken in the city and in some other parts of the country. Since the 19th century, the city, and the country in general, has been a major recipient of millions of immigrants from all over the world, making it a melting pot where several ethnic groups live together. Buenos Aires is considered one of the most diverse cities of the Americas.

The city of Buenos Aires is neither part of Buenos Aires Province nor its capital. It is an autonomous district. In 1880, after the Argentine Civil War, Buenos Aires was federalized and split from Buenos Aires Province. The city limits were enlarged to include the towns of Belgrano and Flores, both now neighborhoods of the city. The 1994 constitutional amendment granted the city autonomy, hence its formal name of Autonomous City of Buenos Aires. Citizens elected their first Chief of Government in 1996. Previously, the Mayor was directly appointed by the President of Argentina.

The Greater Buenos Aires conurbation includes several surrounding cities, which are located in the neighbouring districts of the Buenos Aires Province. It constitutes the fourth-most populous metropolitan area in the Americas. It is also the second largest city south of the Tropic of Capricorn. Buenos Aires has the highest human development of all Argentine administrative divisions. Its quality of life was ranked 97th in the world in 2024, being one of the best in Latin America.

Aragonese archives record that Catalan missionaries and Jesuits arriving in Cagliari (Sardinia) under the Crown of Aragon, after its capture from the Pisans in 1324, established their headquarters on top of a hill that overlooked the city. The hill was known to them as Bonaira (or Bonaria in Sardinian), as it was free of the foul smell prevalent in the old city (the castle area), which was adjacent to swampland. During the siege of Cagliari, the Catalans built a sanctuary to the Virgin Mary on top of the hill. In 1335, King Alfonso the Gentle donated the church to the Mercedarians, who built an abbey that stands to this day. In the years after that, a story circulated, claiming that a statue of the Virgin Mary was retrieved from the sea after it miraculously calmed a storm in the Mediterranean Sea. The statue was placed in the abbey. Spanish sailors, especially Andalusians, venerated this image and frequently invoked the "Fair Winds" to aid them in their navigation and prevent shipwrecks. A sanctuary to the Virgin of the Buen Ayre would later be erected in Seville.

At the foundation of Buenos Aires, Spanish sailors arrived in the Río de la Plata giving thanks to the blessings of "Santa Maria de los Buenos Aires", "Holy Mary of the Good Winds", who they believed to have given them the good winds to reach the coast of what is today the modern city. Pedro de Mendoza called the city "Holy Mary of the Fair Winds", a name suggested by the chaplain of Mendoza's expedition – a devotee of the Virgin of Buen Ayre – after the Madonna of Bonaria from Sardinia (which is still to this day the patroness of the Mediterranean island). Mendoza's settlement soon came under attack by indigenous people and was abandoned in 1541.

For many years, the name was attributed to a Sancho del Campo, who is said to have exclaimed: How fair are the winds of this land! as he arrived. In 1882, after conducting extensive research in Spanish archives, Argentine merchant Eduardo Madero ultimately concluded that the name was instead closely linked with the devotion of the sailors to Our Lady of Buen Ayre. A second (and permanent) settlement was established in 1580 by Juan de Garay, who sailed down the Paraná River from Asunción, now the capital of Paraguay. Garay preserved the name originally chosen by Mendoza, calling the city Ciudad de la Santísima Trinidad y Puerto de Santa María del Buen Aire ("City of the Most Holy Trinity and Port of Saint Mary of the Fair Winds"). The short form that eventually became the city's name, "Buenos Aires", became commonly used during the 17th century.

The usual abbreviation for Buenos Aires in Spanish is Bs.As. It is also common to refer to it as "B.A." or "BA". When referring specifically to the autonomous city, it is very common to colloquially call it "Capital" in Spanish. Since the autonomy obtained in 1994, it has been called "CABA" (per Ciudad Autónoma de Buenos Aires, Autonomous City of Buenos Aires).