At one time it was the most important city in the region—a bustling commercial center known for its massive monuments, its crowded streets and commercial districts, and its cultural and religious institutions. Then, suddenly, it was abandoned. Within a generation most of its population departed and the once magnificent city became all but a ghost town. This is the history of a pre-Columbian city called Teotihuacan (the Aztec Indians' word for “the place the gods call home”),once a metropolis of as many as 200,000 inhabitants 33 miles northeast of present-day Mexico City and the focus of a far-flung empire that stretched from the arid plains of central Mexico to the mountains of Guatemala. Why did this city die? Researchers have found no signs of epidemic disease or destructive invasions. But they have found signs that suggest the Teotihuacanos themselves burned their temples and some of their other buildings. Excavations revealed that piles of wood had been placed around these structures and set afire. Some speculate that Teotihuacan's inhabitants may have abandoned the city because it had become “a clumsy giant... too unwieldy to change with the times.” But other archaeologists think that the ancient urbanites may have destroyed their temples and abandoned their city in rage against their gods for permitting a long famine.