A picture made up of small parts. Traditionally these parts were made out of terracotta, pieces of glass, ceramics or marble, inlayed into floors and walls. Mosaic has been used as a decorative medium for over five thousand years. It was the Islamic mosaics introduced to Spain by the Moors in the eighth century that inspired the twentieth-century Catalan architect Antoni Gaudí, who arranged pieces of broken glazed tiles with fragments of glass bottles and china plates over walls in the Park Güell and in parts of the cathedral of the Sagrada Familia, in Barcelona. Mosaics also became popular in Mexico, particularly in the art of Diego Rivera and Juan O'Gorman, who used stone mosaics in their murals that were based on socialist ideas and exalted the indigenous and popular heritage in Mexican culture (see Mexican Muralism). This workaday ethic became popular again in the 1970s when artists began rediscovering craft-based techniques. The British artist Matt Collishaw made a ceramic tile mosaic of a woman's face taken from a grainy photograph of a woman found on the internet.