Located about 30 miles (50 kilometers) northeast of modern-day Mexico City, Teotihuacan was one of the largest urban centers in the ancient world. No one knows who built it. The city flourished between 2,100 years ago, when construction began, and about 1,400 years ago, when it went into a period of decline, including a fire that caused great damage. However, even with the decline, the city was never truly "lost" — the Aztecs made regular pilgrimages to the site in later periods.
What the city’s own inhabitants called the city and its structures is unknown. The current name, Teotihuacan, was given to it by the Aztecs and means "the place where the gods were created."
