Juan O'Gorman's most celebrated work due to its creativity, construction technique, and dimensions, are the four thousand square meters murals covering the four faces of the building of the Central Library at Ciudad Universitaria at UNAM. These murals are mosaics made from millions of colored stones that he gathered all around Mexico in order to be able to obtain the different colors he needed. The north side pictures Mexico's pre-Hispanic past and the south facade its colonial one, while the east wall depicts the contemporary world, and the west shows the university and contemporary Mexico. Culture, Modernism and Chevy bombs all in one shot. Wow.