In the 20th century, the city began to grow upwards as well as outwards. The column with the Angel of Independence was erected, the ironwork Legislative Palace, Palacio de Bellas Artes and a building called La Nacional. The first skyscraper, 40-story Torre Latinoamericana was built in the 1950s. The construction of the Ciudad Universitaria from 1950 to 1953 had a noticeable effect on subsequent architecture in the city. The most notable buildings are the Rectoría designed by Salvador Ortega, Mario Pani and Enrique del Moral, the Library, by Juan O’Gorman, Gustavo Saavedra and Juan Martínez de Velasco and the Science Building by Raúl Cacho, Eugenio Peschard and Félix Sánchez. Much of what makes the campus culturally significant is its huge murals that decorate the facades of many of the buildings. These murals were done by Diego Rivera, David Siqueiros and others, with themes relating to Mexican history and identity.