For more than a century, researchers studying Monte Albán in Oaxaca, Mexico, had no idea that just centimeters beneath their feet lay a hidden building that could change the world’s understanding of this ancient capital.
Archaeologists from the University of Oklahoma recently pinpointed the location of a buried building about 30 centimeters beneath the surface of the Main Plaza at Monte Albán — one of the first cities to develop in all of pre-Hispanic Mexico. The team used three geophysical prospection techniques — ground-penetrating radar, electrical resistance and gradiometry — to locate the square structure, which is estimated at 18 meters on a side and with stone walls more than a meter thick. OU researchers are the first to employ gradiometry and electrical resistivity at the site.
The hidden building appears to resemble stone temples of a similar size from Monte Alban that were excavated by Mexican archaeologists in the 1930s. Evidence from these temples indicate they were used for religious practices, including burning incense, making offerings and ritual bloodletting, said Marc Levine, associate curator of archaeology at the Sam Noble Oklahoma Museum of Natural History and associate professor in the Department of Anthropology, College of Arts and Sciences. Researchers continue to analyze data from the new building to see if they can detect other features, like stairways, columns, tunnels or associated offerings.
“This discovery changes our understanding of the history of the Main Plaza and how it was organized and used,” Levine said. “Everything is deeply symbolic here.”
Levine, the principal investigator of the project, said archaeologists typically focus on pyramids, platforms and other structures, but tend to overlook the open areas around these imposing monuments. Researchers around the world now are turning their attention to these open plazas and asking how they were used and what they meant to the people who used them.
Monte Albán was established in 500 BCE and eventually grew to become a powerful regional capital with impressive buildings featuring carved stone monuments with a highly developed artistic style and written language. The Main Plaza was built, expanded and remodeled over 1,000 years before the site’s collapse around 850 CE. Archaeologists have investigated many of the buildings erected around the Main Plaza, but have never focused research on the plaza itself to better examine its role in society. OU researchers hope to develop a clearer picture of what the Main Plaza looked like during its early history and better appreciate the amount of work that went into its construction.“If you think of the National Mall in Washington, D.C., every monument and every building that goes on that mall has a significance and was thought over, carefully planned and oriented in a certain way,” Levine said. “The same goes for Monte Albán.”
It’s difficult, he says, to overestimate the importance of Monte Alban for Mexican cultural heritage; the site’s Main Plaza is even featured on the country’s 20 peso note.
In Mesoamerica, buildings often are oriented toward significant features on the landscape or in the sky. At Monte Albán, most structures are aligned to the cardinal directions, but with some minor variations. Levine said the team will need to examine the newly discovered structure more closely to see if it diverges from the prevailing orientation of buildings at the site, which might imply a different kind of symbolism at work earlier in Monte Albán’s history.
The OU team also used a drone to create a digital map of the Main Plaza and its associated structures. With the help of a supercomputer, the team is creating 3-D images of all the buildings to measure their volume. This will provide a better understanding of the effort required to move all the dirt and construct the buildings. Levine estimates the team will spend about two years analyzing all of their data to complete their study of the plaza.
“We may find some other things that are important that we haven’t had a chance to process yet,” he added.
The project was supported by the National Geographic Society, OU and the Sam Noble Museum. Others involved in the research include Scott Hammerstedt, research faculty at the Oklahoma Archeological Survey; Amanda Regnier, director of the Oklahoma Archeological Survey; Marcus Winter from the Oaxaca center of the Instituto Nacional de Antropología e Historia; and Alex Elvis Badillo from Indiana State University. Detailed results of this project are published in the journal Latin American Antiquity.