The oldest point on Madrid’s "Art Triangle," the neo-classical edifice containing the Museo del Prado has displayed the Spanish royal family’s art collection to the public ever since it opened in 1819. It’s crucial to understand that the works on display reflect the taste of Spain’s sixteenth to eighteenth century monarchs, rather than those of academic curators, as this explains why the bulk of the paintings come from territories under Spanish rule or influence, the extensive representation of court artists, and the dearth of pre-Renaissance works. That said, it’s still one of the world’s greatest art collections.
Simultaneously grandiose and austere, the Prado’s interior remains just as impressive as it must have been when it opened – and consequently you should set aside a full day for even the most cursory examination of the collection as a whole. Whether you have this amount of time or only a few hours, it’s wise to pick up a free map upon entering. Regardless of your particular interest, you shouldn’t miss Diego Velázquez’ "Las Meniñas" (Room 12) and Francisco de Goya’s "Disasters of War" (Room 39), the highlights of unrivalled collections of these two competitors for the title of Spain’s greatest painter.
The other greats of Spain’s rich pre-modern artistic history are amply represented as well, with entire galleries dominated by the works of El Greco (60A-62A), Zurbarán (17A-18A), Murillo, and Ribera, the latter two sharing Rooms 25-29. The eschatological paintings of the Hieronymous Bosch (a native of Spanish-ruled Flanders) are concentrated in Room 58 and sharply contrast with the Prado’s Spanish and Italian works, although his eccentric masterpiece "The Garden of Earthly Delights" (Room 58) would stand out anywhere! The Prado boasts several paintings by Raphael and the great Venetian triumvirate of Veronese, Titian, and Tintoretto but the greatest Italian work in the collection is Caravaggio’s "David Defeating Goliath" (Room 65).
I’ve provided these room numbers as the free map is rather basic and nearly all the labeling inside the galleries is in Spanish. I suspect these to be part of a concerted plan to convince foreign visitors to purchase painter-specific gallery guides from machines strategic placed in the Prado’s most visited galleries for €1 each. A rather more shameless fundraising ploy is the overpriced fare in the Prado’s mediocre cafeteria - El Botánico around the corner from the Murillo entrance at Calle Ruíz Alarcón 27 offers much tastier options!
Visiting the Prado requires some planning; it’s open 9am to 7pm Tuesday to Saturday, and 9 am to 2 pm on Sunday, but admission is free only on Sundays and after 2:30pm on Saturday, with the result that the museum tends to be most busy at these times. In addition, if you’d like to see the typically excellent temporary exhibitions (for which there is invariably a line) you have to enter by the northern Puerta de Goya, otherwise it’s better to use the far less busy southern Puerta de Murillo.