Mexico City was originally built by the Aztecs in 1325 on an island they made in Lake Texcoco. They made the island by dumping soil into the lake till an island was formed. The city was called Tenochtitlan by the Aztecs until Cortez came and nearly completely destroyed it in the siege of Tenochtitlan in 1521. It wasn’t officially called Mexico City until 1585 but was called México Tenochtitlán. Cortez used Aztec slaves to build the Mexico City Metropolitan Cathedral with the ruins of the Aztec temple, Templo Mayor, the Aztec god of war, to heighten the Spanish power in the newly conquered state. Mexico City eventually became home to twenty-one million people, making it one of the largest cities in the world. Due to the fact that twenty-one million people live in Mexico City, they drink around 287 billion gallons of water a year, seventy percent of that coming from the lake below Mexico City, causing it to sink in the ground. Mexico City has sunk thirty-two feet in the last sixty years. The main square, Zócalo, is one of the biggest squares in the world with a total of 57,600 square meters. The Mexico City Metropolitan Cathedral is located on one end of Zócalo and a massive Mexican flag is located in the center of the square. The Cathedral’s full name is, The Metropolitan Cathedral of the Assumption of the Most Blessed Virgin Mary into Heaven, or in Spanish, Catedral Metropolitana de la Asunción de la Santísima Virgen María a los cielos.