The largest urban area in North America isn't NYC or LA - it is Mexico City. With a population of over 21 million people in the greater Mexico City area, it is also the largest Spanish-speaking city in the entire world.
The Aztecs were led to the location by a sign from their god, Huitzilopochtli, who pointed to the site by showing them a golden eagle perched on a prickly pear devouring a rattlesnake. The city was originally built on an island of Lake Texcoco by the Aztecs in 1325 as Tenochtitlan, which was almost completely destroyed by the Spanish in 1521. The lake is still there, too - which is why parts of the city have sunk more than 30 feet in the last 100 years.
When Hernan Cortes invaded Mexico in 1521 he marched toward what was described as a "golden city" - Tenochtitlan. Since then, Mexico City has grown far beyond the island that it once occupied. It now covers the entire Valley of Mexico and is one of the most productive and culturally important cities in the world. You can still see the remnants of the old Aztec city in some surviving temples and in the waterways of Xochimilco, called chinampas.
