The Aztec Calendar, also known as the Piedra del Sol (The Sun's Stone), was carved 52 years before the fall of the Mexican empire (1521 AD). This sculpture is 3.60 meters in diameter (12 ft.), and weighs 24 tons. It was created upon a monolith gouged from the lower slopes of the Sierra Grande de Cuyuacan and had to be dragged by fifty thousand men through neighboring towns to be transported to Tenochtitlan the Aztec capital. Its first setting was the white, smooth patio of a ceremonial area called Cuauhxicalco, where it received the incense, music and songs of the Indians who read in it the measures, memories and prophecies of their cosmogonist times. Upon the surface of the Piedra del Sol were described the movements of the heavens and the cycle which counted twenty-day months, eighteen-month years and centuries which renewed themselves every fifty two years. According to its measures, four great solar eras took place prior to the era we live in today. Our era, which corresponds to the fifth sun, began the day called Omey Acatl and will end buried by the devastation caused by a great earthquake.
In the days of the Spanish colony, the Aztec calendar was part of the pagan memory which the Christian missionaries tried to eradicate. In 1559, at the orders of the Archbishop of ivexico Fray Alonso de Montufar the calendar was thrown to the bottom of a creek, During the next 231 years the sculpture was covered by the remains of Tenochtitlan which were used as the foundation of the brand-new buildings of New Spain's capital. In 1790 it was found practically at the surface, becoming unburied due to sewer work which was taking place in the Plaza Mayor. No longer had a threatening relic of idolatry from that time on, it begun to be considered as "a valuable monument of Indian antiquity" and remained exhibited for over one hundred years to the side of the western tower of the city's Cathedral. After it was reproduced on paper during the 19th Century for the first time by the forerunner of Mexican archaeology Antonio de Leon y Carna, its image multiplied and evolved. From being an ornamental detail in the landscape of the City of Palaces it became the emblem of an entire nation: the trace of a glorious and idyllic past which was claimed by a land in struggle, in search of its identity and independence. Its definitive consecration as the homeland's symbol took place in 1885 when it was shown as the central piece in the Monolith Hall of the National Museum. In1964 it entered its next museum space, the National Museum of Anthropology a place of honor which it has maintained since.