Madrid (English pronunciation: /məˈdrɪd/; Spanish: [maˈðɾið]) is the capital and largest city of Spain. The population of the city is roughly 3.3 million (as of December 2009); the entire population of the metropolitan area (urban area and suburbs) is calculated to be nearly 6 million. It is the third-most populous municipality in the European Union after Greater London and Berlin, and its metropolitan area is the third-most populous in the European Union after Paris and London. The city spans a total of 698 km² (234 sq mi).

The city is located on the river Manzanares in the centre of both the country and the Community of Madrid (which comprises the city of Madrid, its conurbation and extended suburbs and villages); 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. The current mayor is Alberto Ruiz-Gallardón from the People's Party (PP). He has been in office since 2003, when he left the Presidency of the Autonomous Community of Madrid and stood as the candidate to replace outgoing mayor José María Álvarez del Manzano, also from the PP. In the last local elections of 2007, Ruiz-Gallardón increased the PP majority in the City Council to 34 seats out of 57, taking 55.5% of the popular vote and winning in all but two districts.

Madrid urban agglomeration has the 4th largest GDP on the continent amounting 230 billion euro in 2009. 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, as well as the headquarters of three of the world's 100 largest companies (Telefónica, Repsol-YPF, Banco Santander).

Madrid is the 10th most livable city in the world according to Monocle magazine.

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 huge Royal Palace of Madrid; the Teatro Real (Royal theatre) with its restored 1850 Opera House; the Buen Retiro park, founded in 1631; the imposing 19th-century National Library building (founded in 1712) containing some of Spain's historical archives; an archaeological museum; and three superb art museums: Prado Museum, which hosts one of the finest art collections in the world, the Museo Nacional Centro de Arte Reina Sofía, a museum of modern art, and the Thyssen-Bornemisza Museum, housed in the renovated Villahermosa Palace.

Madrid has been occupied since pre-historic times, in the Roman era this territory belonged to the diocese of Complutum (present-day Alcalá de Henares). There are archeological remains of a small village during the visigoth epoch.

During the Spanish Golden Age, Madrid knew its ultimate glory; El Escorial, the great royal monastery built by King Philip II of Spain, invited the attention of some of Europe's greatest architects and painters. Diego Velázquez, regarded as one of the most influential painters of European history and a greatly respected artist in his own time, cultivated a relationship with King Philip IV and his chief minister, the Count-Duke of Olivares, leaving us several portraits that demonstrate his style and skill. El Greco, another respected artist from the period, infused Spanish art with the styles of the Italian renaissance and helped create a uniquely Spanish style of painting.

Some of Spain's greatest music is regarded as having been written in the period. Such composers as Tomás Luis de Victoria, Francisco Guerrero, Luis de Milán and Alonso Lobo helped to shape Renaissance music and the styles of counterpoint and polychoral music, and their influence lasted far into the Baroque period which resulted in a revolution of music.

Spanish literature blossomed as well, most famously demonstrated in the work of Miguel de Cervantes, the author of Don Quixote de la Mancha. Spain's most prolific playwright, Lope de Vega, wrote possibly as many as one thousand plays during his lifetime, of which over four hundred survive to the present day. Juan de Herrera, a renowned Renaissance architect designed the Plaza Mayor, in the city, who was built during the Habsburg period is a central plaza. It is located only nearby from another famous plaza, the Puerta del Sol.