Flying high above the Zocalo, the huge Mexican flag that must be at least four stories tall, waves in the wind. The flag carries particular significance at this particular location. According to an Aztec legend, the gods said that a city should be built at the very spot where an eagle is seen with a serpent in hand. Where was the spot where this happened? In the vicinity of where this large flag stands today. And that city chosen by the gods? Mexico City.