Palacio de Cristal (Crystal Palace) inside Retiro Park, Madrid. Built in 1887, this striking building served as a greenhouse for the Exposition of the Philippines held that same year. In its modern incarnation, the Palace functions as an art gallery for temporary exhibits. The architect, Ricardo Velazquez Bosco, also designed the art exhibition space now known as the Palacio de Velazquez. That palace, also a gallery for temporary exhibitions, is located about 100 yards away, to the north.