Begun sometime between the years 200 BCE and 150 BCE, Teotihuacán was the first true metropolis in the Western Hemisphere. It reached the climax of its development between 200 and 500 CE. By the Eighth Century, when its population had reached some 200,000 people, its decline had begun. Theories abound as to the causes of the decline: overpopulation, disease, internal power struggles or overexploitation of natural resources. In any event, the city had been abandoned at least five centuries before the arrival of the Spanish. There is evidence that Teotihuacán's ceremonial buildings were systematically burned, suggesting a purposeful destruction of the city.
Centuries after it had been abandoned, the Mexica (Aztec) elite made pilgrimages to the ruins of Teotihuacán, believing it to have been the birthplace of the gods. Despite its size and grandeur, however – and the fact that Teotihuacán outlived its contemporary, Imperial Rome – very little is known about the people actually who built this magnificent city.
Visiting Teotihuacán today, more than a millennium after its demise, remains an overwhelming experience. The ruins are dominated the imposing Pyramid of the Sun, the third largest pyramid in the world, which towers over the broad, perfectly straight Avenue of Dead – a two-mile boulevard extending from the Pyramid of the Moon in the north to the Citadel and Temple of Quetzalcóatl in the south. Smaller temples and ceremonial platforms line the Avenue of the Dead. Although impressive enough today, it must be remembered that at its height, all of these monumental structures would have been covered with stucco and brightly painted.
The base of the Pyramid of the Sun (738 feet) is nearly as broad as the Great Pyramid at Giza, yet at 213 feet is less than half the height the Egyptian pyramid. Its western face is aligned with the Avenue of the Dead and both deviate from true north by 17 degrees. Because of this deviation, the facade of the pyramid is perfectly aligned with the setting sun on May 19 and July 25 – the two days of the year when the noon sun is exactly above the peak of the pyramid. During Teotihuacán's reign, the Pyramid of the Sun was topped by a temple. Today, a climb to the top rewards visitors with expansive views over the entire site and surrounding countryside.
Although smaller than the Pyramid of the Sun, the Pyramid of the Moon (492 feet at the base; 138 feet high) appears just as prominent for two reasons: first, it is conspicuously placed at the end of grand Avenue of the Dead; and second, it is built on the highest part of the site and thus its summit is the same height as its larger counterpart. A climb up the narrow steps offers visitors a wonderful view straight down the Avenue of the Dead and overlooks the smaller temples and platforms that surround the Plaza of the Moon at the pyramid's base.
Recent archeological excavations under the Pyramid of the Moon reveal that it was built in seven stages over the period from 100 to 400 CE, each stage building on and enlarging the prior. Three of these stages were dedicated by human and animal sacrifices. For more information and photos of the archeological discoveries, see National Geographic Magazine's "Pyramid of Death".
Near the main ruins of Teotihuacán are several smaller sites (Tetitla, Atelelco and Tepantila) where former lodgings are partially restored and some ancient paintings are still visible. Unfortunately, the guide in charge of our visit to Teotihuacán spent far too much time on these minor sites and, as a result, we were pressed for time at the main site and never had a chance to see the structures at the southern end of the Avenue of the Dead, including the Citadel, the Temple of Quetzalcóatl and the site's museum, all of which are reportedly well worth seeing. Ah well, I guess I will just have to go back someday.