Transcription: When the Spaniards conquered Mexico, they described Montezuma's capital Tenochtitlan in such vivid terms that for centuries it seemed that the Aztec stronghold must have been the greatest city of pre-Columbian America. Yet only 25 miles to the north of Tenochtitlan was the site of a city that had once been even more impressive. Known as Teotihuacan, it had risen, flourished and fallen hundreds of years before the conquistadors entered Mexico. At the height of its power, around AD 500, Teotihuacan was larger than Imperial Rome. For more than half a millennium, it was to Middle America what Rome ...