At the time of the Spanish conquest in 1521, the Aztec capital city of Tenochtitlan was among the largest cities in the world, with perhaps as many as 200,000 inhabitants. In less than 200 years, it evolved from a small settlement on an island in the western swamps of Lake Texcoco into the powerful political, economic, and religious center of the greatest empire of Precolumbian Mexico. Tenochtitlan was a city of great wealth, obtained through the spoils of tribute from conquered regions. Of astounding beauty and impressive scale, its towering pyramids were painted in bright red and blue, and its palaces in dazzling white. Colorful, busy markets with a bewildering array of foods and luxuries impressed native visitors and conquering Spaniards alike.
Most of the construction in Tenochtitlan took place during the reigns of four Aztec kings beginning in the 1470s. Built largely upon land reclaimed from Lake Texcoco, the city was laid out on a grid, inspired by the still visible ruins of the ancient city of Teotihuacan of a thousand years earlier. Its network of streets and canals teemed with canoes that transported people and goods within the city and across the lake to towns on the shore, to which it was linked by three raised causeways. Two aqueducts supplied fresh water. At the heart of Tenochtitlan was the Sacred Precinct, the religious and ceremonial center not just of the city, but of the empire as well. Surrounded by a masonry wall of serpents, this enclave of about 380 by 330 yards could hold more than 8,000 people within its precincts. The temples of the most important Aztec gods were here. There was also a ballcourt, priests' quarters, and schools for training young noblemen for the priesthood. Adjacent to the Sacred Precinct, sumptuous palaces of the kings and nobles included beautiful gardens, aviaries, and zoos. Administration buildings were there as well. Commoners lived at a distance and were organized into neighborhoods, called calpulli, with their own local temples and markets. Those populations included laborers and farmers as well as craft specialists such as potters, weavers, sculptors, lapidaries, featherworkers, and soldiers.
On a fateful day in August 1521, life in this magnificent urban center changed forever. Shortly after the fall of Tenochtitlan, the Spaniards razed the already devastated city and built the capital of the Viceroyalty of New Spain on its ruins. They named the new metropolis Mexico City, which today, again, is one of the most populous cities in the world.