Monasterio de las Descalzas Reales
This collection of fantastic, if occasionally brutally themed, religious art, including pieces by Peter Paul Rubens, is in an appropriately creaky and forbidding 16th-century working convent smack in the heart of Madrid’s central district. The art can be viewed only on a tour (5 euros, about $6.50), and Madrileños and tourists alike line up several times a day for the privilege. The pièce de résistance is the tapestry room, a hushed and softly lit space with massive handwoven tapestries displaying biblical scenes in lurid color. Unfortunately, it’s all too brief on the tour and individual wanderings are a strict no-no. Tours are in Spanish, but well worth it even if you don’t speak the language.