A team led by University of Arizona archaeologists has found the oldest known monumental structure of the Maya culture.
The Nature paper supports a changing narrative of how of how Maya society developed.
The human-built plateau of Aguada Fénix in what is now the Mexican state of Tabasco sprawls almost a mile long and a quarter-mile wide, and rises 30 to 50 feet above the ground.
Surrounding it are several complexes arranged in patterns that reoccur throughout Maya sites in the region, along with an arrangement of artificial reservoirs and wetlands skirted by nine causeways, one stretching four miles long.
Built while the Maya were still migratory, it challenges the idea that cities and monuments arise solely from established settlements.
"We get dates that go to 1200 B.C. now, so that makes it early," said coauthor Daniella Triadan of UA's Department of Anthropology.
Triadan said Aguada Fénix shows "the beginning of what is Maya" — the origin of a pattern followed by other cultural sites for years to come.
"This is something that we think started at Aguada Fénix, but then it became this idea of how you have to construct ritually important sites," she said.
She and lead author Takeshi Inomata, also of UA, found the site using excavations and LIDAR, a light-based ranging system not unlike high-resolution radar.
By piercing dense forests, observing remote areas or revealing rectilinear patterns on the ground, LIDAR lets archaeologists see ruins hidden to the naked eye.
The Aguada Fénix site was already bisected by a railway, an airstrip and at least one road, yet only after the team stitched together LIDAR observations did they grasp its full scope and scale.
"It looked like a natural hill until we realized what this thing actually was because it's so huge. When you walk there, it looks like the landscape," said Triadan.
A longstanding archaeological rule-of-thumb holds that built societies arise when hunters and gatherers settle down to farm, forming rural settlements that later mature into cities.
Along the way, societies develop the sort of leadership hierarchy and social and physical infrastructure needed to build large moments and ceremonial sites like Aguada Fénix.
"We're talking thousands of person-days to construct it. And just having that vision too, right? I mean, on the landscape, how do you conceptualize something that's almost a mile long?" said Triadan.
But work at places like Göbekli Tepe in Turkey — and the team's own research at Ceibal in the Petén Department of Guatemala — suggests monumental structures can predate settlements.
The earliest known Maya example of such a monument, Aguada Fénix was built at the dawn of the Middle Preclassic period (1000-350 B.C.), when archaeologists traditionally believe Maya civilization was slowly developing into small villages and just beginning to produce pottery.
Though flirting with agriculture, people there likely still hunted, gathered and fished to supplement their crops.
The authors believe the builders might have been influenced by the older Olmec center of San Lorenzo, in the modern Mexican state of Veracruz, or by a more contemporary Olmec site, La Venta, in present-day Tabasco.
San Lorenzo flourished earlier, around 1400-1150 B.C., whereas La Venta's dominance possibly occurred after 800 B.C.
Where archaeologists fall on that subject depends on how much they think the Olmecs influenced the Maya — an old and enduring debate.
For Triadan and Inomata, the evidence at Ceibal didn't support granting full credit to the Olmecs or the Maya. They see complex connections extending throughout the region, centered on the Usumacinta River, which could have provided a valuable water route for people and goods to the Gulf Coast of Mexico.
