Teotihuacan is a vast Mexican archaeological complex northeast of Mexico City. The Pyramid of the Sun is the largest building in Teotihuacan, believed to have been constructed about 200 CE, It was built by hand more than a thousand years before the swooping arrival of the Nahuatl-speaking Aztec in central Mexico. But it was the Aztec, descending on the abandoned site, no doubt falling awestruck by what they saw, who gave it a name: Teotihuacan.

A famed archaeological site located fewer than 30 miles (50 kilometers) from Mexico City, Teotihuacan reached its zenith between 100 B.C. and A.D. 650. It covered 8 square miles (21 square kilometers) and supported a population of a hundred thousand, according to George Cowgill, an archaeologist at Arizona State University and a National Geographic Society grantee.