Mexico City (Civ6)/Civilopedia

The sprawling megalopolis of Mexico City began as an Aztec settlement on an island in Lake Texcoco, but today encompasses one of the largest cities by urbanized land in the world, a massive center of finance, manufacturing, government and culture.
When the Aztecs left their homeland and settled in the high valley of Mexico in the 14th Century, they united with the local Mexica tribes, and looked to settle on the shores of Lake Texcoco. The legend tells that a priest received a vision from the Aztec god Huitzilopochtli—they were to settle where they saw an eagle, perched on a prickly pear cactus, with a snake in its beak. This image of eagle, snake, and cactus still features on the Mexican flag, and has long been one of Mexico's national symbols. The name of the new Aztec city was Tenochtitlan, and it was originally on a tiny island in Lake Texcoco.
The Aztecs quickly transformed the lake and the city, creating raised beds of reclaimed lakebed in order to raise their crops. The original island of Tenochtitlan was connected to the land by three causeways, and extensive system of levees, aqueducts, and canals meant that the city was as much traversed by canoe as by foot. There is no analog for this kind of construction in the west, with perhaps Venice being a close approximation (the conquistadors were to draw analogies between the two cities after European contact.) The Aztec capital was a center of trade, with the archeological records showing goods coming from all corners of North and Central America, from beyond the borders of the Aztec empire. The massive complex of Huey Teocalli was a center of the Aztec religion and its practices.
Hernan Cortes and his followers were impressed by the city when they laid eyes on it—and then promptly began to undermine the Aztec empire for Spain, eventually laying siege to the city and forcing its surrender in 1521. The city was renamed Mexico City, and became one of the largest centers of colonial government in the Spanish New World. The Spanish began to drain the water from Lake Texcoco (flooding had long been a problem in the city; Spanish construction techniques had exacerbated the problem) and the city began to grow. The Catholic Church established Mexico City as an archbishophric, raising its prominence further.
Mexico City remained the capital through Mexico's various governments, even as the character of these governments has changed between empires and republics. The city hosted the 1968 Summer Olympics and the World Cup in 1970 and 1986. The city has continued to grow in area and population, and the metropolitan region accounts for almost a fifth of Mexico's GDP, one of the largest capital-to-nation ratios in the world. Some of the problems it faces today are old ones—ecological degradation, income inequality, water quality—but the people of the city continue to respond with their own dynamic zeal and flexibility, in formal and informal social systems, making it an ancient city forever reinventing itself.