The Prado is a great museum, but they do not allow photography. The effect of this on our study of art history is that I won't be able to write surveys of Spanish art like the ones I have written for Dutch, Italian, and French art in the course of this trip. Both Velázquez and Goya worked for kings of Spain and royalty managed to retain their most important works, which are now at the Prado, along with a large group by El Greco.
In addition to the most comprehensive collection of Spanish art in the world, the museum has key works in art history by the masters of European art, such as Hieronymus Bosch, Titian, Dürer, Rubens, and a wonderful selection by Veronese. The building was purpose-built to house art and the light was wonderful for photography throughout. It was very frustrating not to be able to capture this great art.
Nevertheless, we spent two wonderful days at the Prado, taking the cab in each morning and enjoying lunch in their excellent cafeteria. Both days were rainy and damp, unusual weather for Madrid in September.