How on earth would you feed a city of over 200,000 people when the land around you was a swampy lake? Seems like an impossible task, but the Aztec managed it by creating floating gardens known as chinampas, then they farmed them intensively.
The Aztec Calendar Stone, Mexica Sun Stone, Stone of the Sun (Spanish: Piedra del Sol), or Stone of the Five Eras, is a large monolithic sculpture that was excavated in the Zócalo, the main square of Mexico City, on December 17, 1790. It was discovered while Mexico City Cathedral was being repaired. The stone is approximately 12 feet (3.7 m) across and weighs approximately 24 tons.