The Escorial is really a great site to visit - it is (supposedly) the world's largest Renaissance building and houses Spain's royal pantheon, yet is built in a somewhat modest style befitting a monastery, which it also is. Built in the shape of a gridiron, the instrument of martyrdom of St. Lawrence, it consists of the monastery, a school, and the Royal Palace commissioned and first inhabited by Philip II. His quarters are modestly furnished, but the church, the library, and the pantheon are extremely impressive, although not extravagant. It is set next to a pretty village just about an hour or so from Madrid, and definitely worth a visit for anyone interested in Spain's Golden Age.