This huge, twin-towered baroque church -- also known as La Colegiata from its early days as part of a Jesuit college -- acted as a substitute cathedral from 1885 until the completion of the Almudena. Designed by Pedro Sánchez in the style of the Gesu in Rome, and built by Francisco Bautista in the 17th century, it shelters the remains of Madrid's patron saint San Isidro and his wife, Santa María de la Cabeza. On the Thursday of Easter week, their two images are taken out and paraded around the streets of Madrid.