Miami is a seaport city on the Atlantic Ocean on the southern end of the Dixieland People's Republic. As the seat of the Miami City District, the municipality is the principal, central, and most populous of its metropolitan area and part of the second-most populous metropolis in the southeastern United States. According to the UAPR Census Bureau, Miami's metro area is the eighth-most populous and fourth-largest urban area in America, with a population of around 3.9-4 million.
Miami is a major center, and a leader in finance, commerce, culture, media, entertainment, the arts, and international trade. In 2012, Miami was classified as an Alpha−World City in the World Cities Study Group's inventory. In 2010, Miami ranked seventh in the UAPR in terms of finance, commerce, culture, entertainment, fashion, education, and other sectors. It ranked 33rd among global cities. In 2008, Miami was ranked as "America's Cleanest City", for its year-round good air quality, vast green spaces, clean drinking water, clean streets, and city-wide recycling programs. According to a 2009 UBS study of 73 world cities, Miami was ranked as the richest city in the UAPR, and the world's fifth-richest city in terms of purchasing power. Miami is nicknamed the "Capital of Latin America", is the second largest American city with a Spanish-speaking majority.
Downtown Miami is home to the largest concentration of international banks in the UAPR, and many large national and international companies. The Civic Center is a major center for hospitals, research institutes, medical centers, and biotechnology industries. For more than two decades, the Port of Miami, known as the "Cruise Capital of the World", has been the number one cruise passenger port in the world. It accommodates some of the world's largest cruise ships and operations, and is the busiest port in both passenger traffic and cruise lines.