this same lava attribute, in what is now the Ecological Reserve of Anahuacalli. The Anahuacalli Museum is the only museum in Mexico that has an ecological zone of 28000 square meters that remains in a wild state and has water outcrops that enrich the beauty of the landscape. This green area protects flora and fauna typical of the volcanic soil of the place, as well as orchids, edible and medicinal herbs, Begonia del Pedregal and shrubs that are not found in any other green area in Mexico. This ecological reserve can be contemplated with a panoramic view from the roof of the museum. Also, it can be visited through guided tours on Saturdays and Sundays. Pre-columbian art collection Diego Rivera (1886–1957) began collecting pre-Columbian art in his childhood. In 1906, he had to leave this first collection under the care of his mother, when he went to live and work in Europe. Upon his return in 1921, he was forced to restart his collection because his mum told him that she had to sell it due to economic problems. That same year, Rivera restarted the gradual acquisition of the pre-Columbian artworks that are currently exhibited at the Anahuacalli. Since the 1930s, Diego had the intention of depositing his collection in a specific place, designed according to his ideas. At that time, the muralist was already collaborating with the cultural authorities of the government in turn. In 1934, once the Palace of Fine Arts was completed, the Escultura Mexicana Antigua (Ancient Mexican Sculpture exhibition) was held. Maestro Rivera collaborated with this exhibition, contributing twelve pieces of the one hundred and thirty-nine works that composed this exhibition. Juan Coronel Rivera, historian, writer and grandson of the painter, declares: "When the collection was very incipient, around 1934, he actually had very selected pieces; each one of them he placed on a base. Later, when the quantity was overwhelming, when it went up to 30,000 pieces, he just placed them where they fit". By the year of his death, in 1957, master Rivera had more than 40,000 pieces collected. Dolores Olmedo (1908–2002), Rivera's former patron, counted 59,400 pieces. Diego Rivera's interest in the pre-Hispanic past coincides with the years in which nationalist thinking was formed as a result of the Mexican Revolution. Like his contemporaries, he did not only value the remains of pre-Columbian cultures, but also considered the pieces from Tlatilco, Teotihuacán and