Museo del Prado

Spain's national art museum and the reason a lot of people come to Madrid in the first place. Velázquez's Las Meninas, Goya's black paintings, Bosch's Garden of Earthly Delights.

Free entry in the last two hours of the day: Monday to Saturday 18:00–20:00, Sunday 17:00–19:00. The queue starts forming about 45 minutes before, and it moves. You will not see everything in two hours — pick three rooms and actually look at them.

Plan roughly three hours for a paid visit. There is a cloakroom, and large bags are not allowed in the galleries.

Hours and prices change — check the official site before you go.