The capital city of Argentina is Buenos Aires. It is the country's largest city and serves as the national center of commerce, industry, politics, culture, and technology. Buenos Aires is located on the shore of the Río de la Plata, about 150 miles from the Atlantic Ocean. It has a population of over 3 million in the city proper, with the Greater Buenos Aires metropolitan area housing over 17 million people. The city is known for its vibrant culture, European architecture, and its historical significance as a major center of immigration and political power in Argentina. Buenos Aires is also an autonomous city, separate from Buenos Aires Province, and has its own local government. In summary, Buenos Aires is the capital and largest city of Argentina, renowned for its cultural richness and economic importance.