They are studying ancient Teotihuacan with the technique of aerial mapping

At its peak, Teotihuacan was one of the largest cities in the world, with over 100,000 people in an extension of what is now central Mexico. Now a team of archaeologists have used aerial survey technology to find out how the landscapes have been extensively modified by the people who live there.

The team was trying to understand how ancient Teotihuacan was designed and how the modern urban landscape was built upon it. Built between 100 a. c and 450 d. C., Teotihuacán is located approximately 30 miles northeast of Mexico City, making it an integral part of the modern urban landscape.

The researchers found that the builders of the ancient city dug so much, that they dug the bedrock of other construction sites in the city, and that 65% of urban monuments today are built on the same alignment as Teotihuacan. The team also found that 205 of the ancient city’s landmarks had been destroyed by mining operations since 2015. Their findings They posted it This week on PLOS One.

“We find that we need to redefine what cityscapes were like in the past and what their long-term legacies are in modern landscapes,” said Nawa Sugiyama, an anthropologist at the University of California Riverside and lead author of the latest study. In an email to Gizmodo. “People have modified the built environment on a large scale for thousands of years, and in urban contexts, such as the ancient city of Teotihuacan, they have been altering the course of rivers, altering the terrain and affecting the agricultural potential of the area.”

“These changes made nearly 2,000 years ago continue to affect the way we build our buildings, align our roads and build terraces over our crops,” Sugiyama added.

Technology used by the team lidar, a rare and now widespread method for non-invasive archaeological studies. Lidar is short for “Light Detection and Range,” which is pretty much what the technology does: it shoots light at a target’s surface and measures the time it takes for the light to recover. Based on these intervals, archaeologists can see subtle changes in elevation at very high resolution. Lidar can traverse jungle canopies, which is useful for finding hidden settlements for centuries, as was the case with the large Mayan settlement north of Tikal. Discover in 2018.

The engineers who designed Teotihuacan also doubled the San Juan and San Lorenzo rivers, which run through the city. Rivers bent to adapt to astronomical alignment of the city, another example of the impressive effort and expertise that went into building the city. “Controlling the flow of water was not only a means of integrating the course of the river into the planning of the cosmic city of Teotihuacan, but also a means of demonstrating its mastery of these natural elements, an feat that required the hands of thousands of workers,” said Sugiyama. .

Unfortunately, underground structures are not visible to LIDAR: the technology simply detects changes in the ground’s elevation. Therefore, the team does not know which of the 200-something building was destroyed when parts of the valley were excavated in anticipation of an international airport, its plans have since been scrapped. Still, in May The Mexican government condemned A special building project that damaged and destroyed elements of the historic city.

Thomas Garrison, an archaeologist and remote sensing specialist at the University of Texas at Austin, who was not affiliated with the study, said in an email. “By showing direct links between ancient Teotihuacan and modern settlements surrounding the ruins, this study presents a compelling case for why archeology is an important discipline in the twenty-first century rather than just a colonial effort to fit into cultural heritage.”

The research team will collaborate with the Mexican Government’s Office of Culture (the National Institute of Anthropology and History) in using the maps as a reference point for the current state of Teotihuacan’s cultural heritage. The mission is really about discovering what is there and making sure that it does not disappear with further human development.