Armed with machetes and chainsaws, hacking through fallen trees and wading through thick undergrowth, the archaeologists carved a path over rocky paths.
Finally, they reached their destination in Mexico’s Yucatán Peninsula: a hidden city where pyramids and palaces towered above the crowd more than 1,000 years ago, with a ball court and terraces now buried and overgrown.
Mexico’s National Institute of Anthropology and History applauded their work late last month, saying they had discovered an ancient Mayan city in “a vast area virtually unknown to archaeology.”
“These stories about ‘lost cities in the jungle’ — very often these things are pretty petty or made up by journalists,” said Simon Martin, a political anthropologist who was not involved in the work. “But this is much closer to the real deal.”
The team of archaeologists that discovered the ruins named them Ocomtún, using the Yucatec Maya word for the stone columns found around the ancient city.
The Mexican Institute described the site, in the state of Campeche, as once an important center of Mayan life. During at least part of the Classic Maya era – around AD 250 to 900 – it was a densely populated area. Today it’s part of a vast ecological reserve where vines and tropical trees graze boots and tires, and fresh water slides through the porous limestone terrain.
“I’m often asked why no one got there, and I say, ‘Well, probably because you have to be a little crazy to go there,'” says Ivan Sprajc, the study’s lead archaeologist and professor at a Slovenian research center, ZRC SAZU. “It’s not an easy job.”
The work has been revolutionized over the past decade by lidar, a technology that uses airborne lasers to pierce dense vegetation and reveal the ancient structures and man-altered landscapes beneath. But in the end it still comes down to tough trips.
“Sprajc does exactly the right thing; using lidar as a research tool, but not interpreting the results without veracity,” said Rosemary Joyce, an anthropologist at the University of California, Berkeley.
She said in an email that a newly documented site was unlikely to “substantially alter historical narratives,” but that such work could help researchers “see more variation in the ways different Maya communities lived during the Classic period.”
And it remains “unusual to find such a large site that nobody knows about,” said Scott Hutson, an archaeologist at the University of Kentucky.
For decades, archaeologists relied on the help of descendants of the Maya to identify and excavate the ancient sites they knew. But because this part of Campeche has been a reservation for decades, Dr Hutson said, “there just aren’t any archaeologists walking through this area at all.”
Dr. Martin called the region an “empty zone” on archaeologists’ maps.
Dr. Sprajc, 67, said the expedition to Ocomtún lasted about a month and a half, “relatively short” compared to the usual two months or more. The trip is made during the dry season, which can be daunting, but less than long trips in the rainy season.
Surrounded by wetlands, Ocomtún includes pyramids, plazas, elite residences and “strange” complexes of structures arranged almost in concentric circles, said Dr. Sprajc. “We don’t know anything about that about the rest of the Maya lowlands,” he said.
The largest documented structure in Ocomtún was a pyramid about 15 meters high, of which Dr. Sprajc said it would have been a temple. It and some other structures stood on a large rectangular platform, raised about 9 meters above the ground and with sides more than 80 meters long.
“Its scale and location alone make it an important site,” said Charles Golden, an anthropologist at Brandeis University. He said excavations could help answer a host of questions about who lived there and their relationship to other Mayan cities and settlements.
People seemed to have left Ocomtún around the same time as other Maya cities, from about 800 to 1000 AD, a decline that researchers attribute to factors such as drought and political strife.
A hint to those conflicts may have been found on the site. While most of the structures were unadorned, the team found, upside down a flight of stairs, a block of hieroglyphics that appears to be from another Mayan settlement.
Such monuments were sometimes “brought from other locations as spoils of war, and this apparently happened in this case,” said Dr. Sprajc.
Dr. Joyce said the image of conquest in the bloc was normal, “so we can have evidence here that Ocomtún was part of the great wars swirling around the great powers” of the Maya world.
The team also found some agricultural terraces, which archaeologists called a sign of the Maya’s widespread modifications to make the harsh environment more favorable to humans. Using hydraulics, water conservation and retention, and landscape engineering such as terracing, the Maya managed to live in “what seem like pretty inhospitable areas today,” said Dr. Martin.
For modern groups in transit, the water must be supplied by truck. Dr. Sprajc said that even after his team excavated about 60 kilometers of motorable path to Ocomtún, it still took five to 10 hours to reach the site because the terrain was so difficult to traverse.
Expeditions like these require huge expenditures, both for the fieldwork and before anyone sets foot in a forest. Lidar scans alone can cost tens of thousands of dollars. Dr. Sprajc found funding not only from his own institution, but also from four Slovenian companies and two American charities: the publishing house Založba Rokus Klett, the railway service Adria kombi, the credit company Kreditna družba Ljubljana, the tourism company AL Ars Longa, the Ken & Julie Jones Charitable Foundation and the Milwaukee Audubon Society.
Other researchers can now seek the funding, permits and supplies needed to excavate Ocomtún, but Dr. Sprajc will not be there. He said he was planning another expedition in March or April next year, heading to another part of Yucatán where lidar imagery has yielded clues.
Fellow scientists, buoyed by the work at Ocomtún, look forward to seeing what his team might find next.
“This shows that in places like Campeche, which on the one hand are quite close to places like Cancún and busy tourist spots, there are still places that no one has really documented,” said Dr. Golden, Brandeis’ anthropologist. “So that’s always exciting that these places still have secrets to reveal.”