Museo Nacional del Prado Madrid, Spain

Considered one of the world's most important art galleries, it exhibits paintings by Goya, Velázquez, Murillo, Zurbarán, El Greco, Ribera, Titian, Boticelli, Tintoretto, El Bosco, Rubens, Van Dyck, Poussin and Durer. Carlos III commissioned Juan de Villanueva to design this beautiful building, which was converted into an art gallery in 1819. In July of 2005, the Council of Ministers approved a EUR44.6 million expansion plan which increases the museum's total space by 50 percent, and allows for 500 more works of the permanent collection to be showcased. On October 30, 2007, the annex opened with a collection of 19th-century Spanish artwork which enabled the Prado to reclaim its glory as a crown jewel of Europe. Come for the art; stay for the architecture.