Central Madrid's other royally endowed Habsburg monastery is quietly nestled in a charming little square between the Royal Palace and Plaza España. Though paling slightly in comparison with the incomparable Descalzas Reales, it still remains by any other standards a must-see. Founded by Margaret of Austria and Philip III in 1611 and rebuilt by Ventura Rodriguez after a disastrous fire nearly destroyed it in 1767, it's inhabited by Augustine Recoletos nuns who remain out of sight in their cloisters during visiting hours. The facade is a fine example of post-Herreran style and inside hides an impressive selection of polychrome sculptures and paintings, highlighted by Ribera's superb portrait of John the Baptist. Most extraordinary of its many salons is the Reliquario, where the solidified blood of Saint Pantaleon, permanently kept in a glass orb, supposedly liquefies for 24 hours every year beginning at midnight on July 27 (the eve of his saint's day). According to legend, if it does not liquefy, disaster will follow. On display all around it are the bone fragments and bronze, copper, and gold reliquaries of other saints and martyrs. The main cloister and church are also well worth a look. Tours are conducted in Spanish.