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News — Have archaeologists already discovered all of the major ancient Maya monuments—or is there still much more to be found? 

That question has divided experts for some time. But in the journal Antiquity, led by a scholar at Northern Arizona University, may put the debate to rest. 

Along with colleagues at Tulane University, Mexico's Instituto Nacional de Antropología e Historia and the University of Houston's National Center for Airborne Laser Mapping, Luke Auld-Thomas, an instructor in NAU’s Department of Anthropology, analyzed a lidar survey of an understudied corner of the Maya civilization in Campeche, Mexico. Looking at 50 square miles of narrow strips and larger blocks of land within a region bigger than Connecticut, the scientists found evidence of a stunning 6,674 Maya structures—some densely arranged, some more dispersed—that archaeologists had never seen before. Some of those structures even comprised the remains of an unknown large city, complete with iconic stone pyramids like those at the famous sites of Chichén Itzá or Tikal.鈥� 

“Our analysis not only revealed a picture of a region that was dense with settlements, but it also revealed a lot of variability,” Auld-Thomas said. “We didn’t just find rural areas and smaller settlements. We also found a large city with pyramids right next to the area’s only highway, near a town where people have been actively farming among the ruins for years. The government never knew about it; the scientific community never knew about it. That really puts an exclamation point behind the statement that, no, we have not found everything, and yes, there’s a lot more to be discovered.” 

Lifting the curtain with lidar 

How did the Maya settlements in this corner of southern Mexico go unnoticed and unstudied for so long? It has a lot to do with how archaeologists once worked, Auld-Thomas said, and how the nature of that work has changed today. 

“For the longest time,” he said, “our sample of the Maya civilization was a couple of hundred square kilometers total. That sample was hard won by archaeologists who painstakingly walked over every square meter, hacking away at the vegetation with machetes, to see if they were standing on a pile of rocks that might have been someone’s home 1,500 years ago.” 

But for the last 10 to 12 years, he said, archaeologists have been able to discover new cities, farming terraces and other traces of the Maya civilization at a much faster clip using light detection and ranging technology, or lidar. The technology allows scientists to scan large swaths of land from the comfort of an office, uncovering anomalies in the landscape that often prove to be pyramids, family houses and other Maya infrastructure. 

For all of lidar’s benefits, there’s one downside: It’s expensive, and granting organizations don’t want to sink money into studying areas that are totally unknown and potentially devoid of Maya history. That’s why one part of Campeche was still a blank spot on archaeologists’ maps—until Auld-Thomas got an idea. 

“Scientists in ecology, forestry and civil engineering have been using lidar surveys to study some of these areas for totally separate purposes,” Auld-Thomas said. “So what if a lidar survey of this area already existed?” 

As it turns out, it did. In 2013, a consortium focused on measuring and monitoring carbon in Mexico’s forests had commissioned a very thorough lidar survey on an area of land about the same size as San Francisco, then left it to gather digital dust. Auld-Thomas unearthed the survey during a deep-dive Google search.  

Auld-Thomas studied the survey and found something stunning: a dense, diverse array of totally unstudied Maya settlements dotted throughout the region, including a full-on city.  

His findings might just settle a heated archaeological debate that’s raged since the advent of lidar. 

“Because lidar allows us to map large areas very quickly, and at really high precision and levels of detail, that gave us a sudden sense of, ‘Oh my god, there’s so much stuff out there we didn’t know about,’” he said. “The counterargument was, we’re still mapping around known sites. We’re taking downtown Tikal and zooming out and mapping around that. What if that means everything we’re mapping is still the exception, not the rule?” 

Auld-Thomas said this survey clearly shows there’s much more of the Maya world to uncover, as the first group of archaeologists believed. 

Using archaeology for good 

What’s the next step in understanding the true reach and density of the Maya civilization? Fieldwork, of course.  

“You can learn a lot from a map, but the one thing you can’t learn is how things evolve through time,” Auld-Thomas said. “As we map larger areas, we need to get out in the field and study individual buildings and the artifacts we recover when we explore them. Being on the ground and getting a sense of when things were built and occupied is what helps us understand how these settlements ebbed and flowed over time.”  

Another logical next step: Partnering with remote-sensing scholars across multiple disciplines to study even more unknown areas. Auld-Thomas is part of a new remote-sensing research cluster at NAU, which will bring together researchers who use lidar to study space, forests, civic infrastructure and more.鈥�  

By partnering with one another, Auld-Thomas said, the scholars will be able to make new headway in each of their research areas and help solve some of the critical problems the globe faces today.  

Auld-Thomas said archaeology can be a problem-solving discipline because it contains historical insights that could help unlock solutions for today’s and tomorrow’s problems. 

“The ancient world is full of examples of cities that are completely different than the cities we have today,” he said. “There were cities that were sprawling agricultural patchworks and鈥� hyper-dense; there were cities that were highly egalitarian and extremely unequal. Given the environmental and social challenges we’re facing from rapid population growth, it can only help to study ancient cities and expand our view of what urban living can look like. Having a larger sample of the human career, a longer record of the accumulated residue of people’s lives, could give us the latitude to imagine better and more sustainable ways of being urban now and in the future.”