Musée du Prado

The Prado is a king's collection made public. For three centuries the Spanish Habsburgs and Bourbons bought and commissioned on a royal scale, and their taste is the museum: Titian and Rubens whom the kings loved, Velazquez who served the Spanish court for most of his life. His Las Meninas hangs at the heart of the building, the painter looking out from behind his own canvas in a room of the old royal Alcazar.

The gallery opened in 1819 in a building the architect Juan de Villanueva had first designed as a hall of natural science. Its walls carry the darker turns of Spanish art alongside its splendour, Goya's Third of May 1808, the firing squad lifting its lanterns in the dark, and the Black Paintings he put straight onto the walls of his own house late in life, deaf and withdrawn, and never meant to show.

The oldest of its great treasures predates that royal Spanish taste, Hieronymus Bosch's Garden of Earthly Delights, the three-panelled vision of paradise, desire and hell, later brought into Philip II's collection and sent to his monastery-palace of El Escorial. Now it draws crowds to what only the court was once allowed to see.