Tenochtitlán was the flourishing capital of the Aztec Empire with an estimated population of between 200,000 and 300,000, a unique system of lake agriculture known as chinampas, and a ceremonial precinct that contained a great pyramid sacred to the Aztec war god Huitzilopochtli. Spanish conquistador Hernán Cortés was chased from the city in 1520, but returned a year later, took the city after a three-month siege, and razed it. What tragedy helped Cortés to defeat the Aztecs this time? Discuss (http://forum.thefreedictionary.com/postst65305_Cort%C3%A9s-Conquers-Tenochtitl%C3%A1n--1521-.aspx)