The Prado and Paseo del Artes, Madrid

The Prado alone ranks with the world's top art museums for the riches of its collections. But add the Reina Sofia National Art Museum, the Thyssen-Bornemisza Museum, and the CaixaForum, all along Madrid's mile-long, tree-shaded boulevard, and you have what may be the world's highest concentration of priceless art treasures. It's no wonder this is known as El Paseo del Arte - Boulevard of the Arts.

After a 2007 expansion that doubled its exhibition space, the Prado added another 12 galleries in 2009 to house a collection of works by Goya and other late 19th-century artists. The Prado has the world's largest collection of Spanish art, an impressive continuum from 12th-century medieval works through the avante-garde movement of the early 20th century, and is especially noted for its works from Spain's golden age by El Greco, Velazquez, and Goya. But its riches are not all Spanish; other highlights are the medieval murals and retablos, paintings by Flemish and Dutch artists (be sure to see the fantasy world of Hieronymous Bosch and works by Rubens and Brueghel), and Italian art (Botticelli, Raphael, Correggio, Titian, and Tintoretto). Highlights of the Reina Sofia's impressive 20,000 works are Picasso's Guernica and works by Miró, Dalí, Dubuffet, Braque, Serra, Calder, and Magritte.