Legend has it that a nomadic people known as the Mexicas made their home in this marshy region after seeing a prophetic vision in the form of an eagle devouring a snake while perched on a cactus, which they took as a sign to settle and found a city... A more probable reason for their move, however, is that they were rejected by neighboring tribes. The city established in 1325 quickly grew, with rafts to provide more workable land, dams, aqueducts and broad avenues. It is thought that when the Spanish colonists discovered Tenochtitlan, it had a population of nearly one million people! A real system of government was in place, with the city divided into districts and an urban-planning department approving the construction of houses, all of which had a garden and steam bath. 1,000 public-service employees were given the task of cleaning the city and gathering excrement, which was used as fertilizer. The market attracted tens of thousands of traders.

Much like the legend of how the city was founded, its decline and destruction were also linked to an omen: when Hernán Cortés and his troops arrived at the city gates, they were thought to be "Teules", demi-gods announcing the return of the deity Quetzalcoatl.