The Pyramid of the Sun is the largest building in Teotihuacan, Mexico, believed to have been built around 200 AD and one of the largest in Latin America. Located on the Avenue of the Dead, between the Pyramid of the Moon and the Ciudedela and in the shadow of the massive Cerro Gordo mountain, the pyramid is part of a large complex in the heart of the city. It is about 66 meters high, at the beginning of the 70s, a study under the pyramid discovered a system of cave and tunnel chambers. In 1987 it became part of the UNESCO cultural heritage.