Date: 150
Owner: Jack Hynes
Source Type: Buildings

This photograph shows the ruins of Teotihuacan, a city built near the valley of Mexico that thrived from around 200 BCE to 700 CE. Although it remains unclear which Mesoamerican civilization built this city, Teotihuacan was a massive center of ritual, commerce, and political control and was larger than any contemporary urban center in either the Americas or Europe. Even the original name of the city is unknown; although the city was already a ruin by the Aztecs' arrival, they named it Teotihuacan ("place of the gods") because of the amazing size of its pyramids, especially the Pyramid of the Sun (seen in the distance in the left of this picture).

What is known, however, is that like many Mesoamerican urban centers, Teotihuacan is laid out with geometric precision to correspond with calendrical and astronomical standards. The "Street of the Dead," the broad avenue running through the center of this photo, aligned the entire city grid on an axis that was offset from the true cardinal directions by 15.5 degrees. Even the suburbs, countryside, and chinampas (see the Agriculture and Science topic) around the metropolis followed this directional orientation.

Anthropologists and astronomers have offered several compelling explanations for why Teotihuacan would be offset at the seemingly arbitrary 15.5 degrees. Some older theories suggest that it was arranged to coincide with the setting of the Pleiades in the year 150 CE (when the city was thought be have been laid out) or that the Street of the Dead lines up with the setting sun on the day when the zenithal sun passes over (this theory, though, involved errors in reckoning the site's latitude). Geographer Vincent H. Malmstrom posited the compelling idea that the offset was based on a relationship between the setting of the sun across from the Pyramid of the Sun, Izapa (an ancient city in southern Mexico), and the Mesoamerican calendar. Based on the sun's azimuth at Teotihuacan (at 19.5 north latitude), he found that the sun would have passed directly over Izapa (at 14.8) on August 13, the day when the Maya believed the world began. Malmstrom thus argues that the specific angular layout of Teotihuacan intentionally referenced the Olmecs, the ur-civilization of Mesoamerica that spread its culture and calendar throughout the region. Although Teotihuacan was built 1000 miles from Izapa and 1000 years after the Olmecs, it reflects the cosmological continuity that mathematics and the calendar gave to millennia of Mesoamerican cultures. The difficulty of conducting (or even explaining) such calculations today bears witness to the genius of ancient Mesoamerican mathematicians.

Reference: Malmstrom, Vincent H. Cycles of the Sun, Mysteries of the Moon: The Calendar in Mesoamerican Civilization. Austin: University of Texas Press, 1997.

CITATION: Jack Hynes. View of Avenue of the Dead and Pyramid of the Sun from the Pyramid of the Moon. 26 May 2006. Public Domain.