Tourists on the roof of La Pedrera (Casa Mila). Built by Antoni Gaudi between 1906 and 1910 for the Mila family, it is as much a sculpture as a building. The facade is an impressive, varied and harmonious mass of undulating stone without any straight lines. The roof shows an exuberant fantasy; the chimneys are vanguard shapes, looking like warriors in a forest of surprising figures. The building was recognized by UNESCO as a World Heritage Site in 1984.