Armed with machetes and chainsaws, cutting down fallen trees and wading through dense bush, archaeologists cleared a path along rocky paths.
Finally, they reached their destination in Mexico’s Yucatán peninsula: a hidden city where more than 1,000 years ago pyramids and palaces rose above the crowds, with a ballcourt and terraces now buried and overgrown.
National Institute of Anthropology and History of Mexico saluted their work late last month, claiming to have discovered an ancient Mayan city in « a vast area virtually unknown to archeology. »
« These ‘lost cities in the jungle’ stories — very often these things are quite minor or are being reported 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 who uncovered the ruins named them Ocomtún, using the Yucatec Mayan 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—between about AD 250 and 900—it was a well-populated area. Today, it’s part of a large ecological preserve where vines and tropical trees growl at boots and tires, and fresh water trickles across the porous limestone soil.
« I’m often asked why no one has come there, and I answer, ‘Well, probably because you have to be a little crazy to go there,' » said Ivan Sprajc, the survey’s lead archaeologist and a professor at a Slovenian research center. ZRC SAZU. « It’s not an easy job. »
The work has been revolutionized in the last decade by lidar, a technology that uses airborne lasers to pierce through dense vegetation and reveal ancient structures and man-made landscapes underneath. But in the end, it’s still an arduous journey.
“Sprajc is doing exactly the right thing; using lidar as a survey tool but not interpreting the results without ground truth,” said Rosemary Joyce, an anthropologist at the University of California, Berkeley.
He said in an email that any of the newly documented sites were unlikely to « materially change historical narratives, » but that such work could help researchers see « more variation in the ways different Maya communities conducted life during the classical 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 have relied on the help of descendants of the Maya to identify and excavate the ancient sites familiar to them. But because this part of Campeche has been a reserve for decades, Dr. Hutson said, « there simply haven’t been archaeologists who have passed through this area. »
Dr. Martin called the region a « blank patch » on archaeologists’ maps.
Dr Sprajc, 67, said the expedition to Ocomtún took about a month and a half, « relatively short » compared to the usual two months or more. The trip was done in the dry season, which can be daunting, but less so than the long trips in the rainy season.
Surrounded by wetlands, Ocomtún comprises pyramids, plazas, elite residences and « strange » complexes of structures arranged almost in concentric circles, said Dr. Sprajc. « We know nothing about it from the rest of the lowland Maya, » he said.
The largest documented structure at Ocomtún was a pyramid about 50 feet high, which Dr. Sprajc said would have been a temple. It and some other structures stood on a large rectangular platform, raised about 30 feet off the ground and with sides more than 250 feet long.
« Because of its size alone, its location, it must be a significant site, » said Charles Golden, an anthropologist at Brandeis University. He said the excavations could help answer a number of questions about who lived there and their relationship to other Mayan cities and settlements.
It appears that people left Ocomtún around the same time they left other Mayan cities, from about AD 800 to 1000, a decline that researchers attribute to factors such as drought and political strife.
A hint of these conflicts may have been found on the site. Although most of the structures were unadorned, the team found, upside down on a ladder, a block with hieroglyphics which appears to be from another Mayan settlement.
Such monuments were sometimes « brought in as spoils of war from other sites, and that’s what apparently happened in this case, » said Dr. Sprajc.
Dr. Joyce said the bloc’s conquest imagery was normal, « so we may have evidence here that Ocomtún was part of the great wars that swirled around the major powers » of the Mayan world.
The team also found some agricultural terraces, which the archaeologists say was a sign of widespread modifications made by the Maya to make the harsh environment more generous for humans. Using plumbing, water conservation and capture, and landscape engineering such as terraces, the Maya were able to live in « what today seems like quite inhospitable areas, » said Dr. Martin.
For modern passing groups, water has to be loaded onto a truck. Dr. Sprajc said even after his team excavated about 37 miles of passable track to Ocomtún, it still took five to 10 hours to reach the site because the terrain was so difficult to traverse.
Such expeditions require huge expenses, both for field work 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 institutionbut also four Slovenian companies and two American charities: the publisher Rokus Klett Publishing Housethe train service Adria vanthe credit company Ljubljana credit companythe tourism company Al Ars Longathe Ken & Julie Jones Charitable Foundation and the Milwaukee Audubon Society.
Other researchers may now be seeking the funding, permits and supplies needed to excavate Ocomtún, but Dr Sprajc will not be among them. He said he was busy planning a new expedition next March or April to another part of Yucatán, where lidar imaging has unearthed clues.
Fellow scientists, encouraged by the work at Ocomtún, are eager to see what his team might discover.
« This shows that in places like Campeche, which on the one hand are quite close to places like Cancún and heavy tourist sites, there are still these places that no one has really documented, » said Dr. Golden, the Brandeis anthropologist. « So it’s always exciting that these places still have secrets to reveal. »