El Escorial
El Escorial was built between 1563 and 1567 by Juan Bautista de Toledo, a Spanish architect who had spent much of his career in Rome, to commemorate Spain's victory over the French at the Battle of St Quentin. It would later become the king's palace and the center of his empire.
Look for the beautiful white Carrara marble statues and paintings by El Greco, as well as other 16th, 17th, and 18th century Spanish and Flemish artists, in the basilica.
It's worth acquiring a map and making a list of highlights because there's so much to see in the towering structures that you could easily spend an entire day here.
Location: Madrid, Spain