Madrid is the capital and largest city of Spain. The population of the city is roughly 3.3 million and the entire population of the Madrid metropolitan area is calculated to be 6.271 million. It is the third largest city in the European Union, after London and Berlin, and its metropolitan area is the third largest in the European Union after London and Paris. The city spans a total of 233.3 square miles. Madrid urban agglomeration has the 3rd largest GDP in the European Union and its influences in politics, education, entertainment, environment, media, fashion, science, and the arts all contribute to its status as one of the world's major global cities. Due to its economic output, high standard of living, and market size, Madrid is considered the major financial centre of Southern Europe and the Iberian Peninsula; it hosts the head offices of the vast majority of the major Spanish companies. Madrid is the most touristic city of Spain, the fourth-most touristic of the continent, and is the 10th most livable city in the world according to Monocle magazine, in its 2010 index. Madrid also ranks among the 12 greenest European cities in 2010. Madrid is currently bidding to host the 2020 Summer Olympics. The city is located on the Manzanares river in the centre of both the country and the Community of Madrid; this community is bordered by the autonomous communities of Castile and León and Castile-La Mancha. As the capital city of Spain, seat of government, and residence of the Spanish monarch, Madrid is also the political centre of Spain. While Madrid possesses a modern infrastructure, it has preserved the look and feel of many of its historic neighbourhoods and streets. Its landmarks include the Royal Palace of Madrid; the Teatro Real (Royal theatre) with its restored 1850 Opera House; the Buen Retiro park, founded in 1631; the 19th-century National Library building containing some of Spain's historical archives; an archaeological museum; and the Golden Triangle of Art, located along the Paseo del Prado and comprising three art museums: Prado Museum, the Museo Nacional Centro de Arte Reina Sofía, a museum of modern art, and the Thyssen-Bornemisza Museum, housed in the renovated Villahermosa Palace.