Lasers revealed 6 ancient civilizations that were hiding in plain sight

• Archeologists beam lasers from the sky to unearth ancient settlements hiding in plain sight.
• Lidar uses laser pulses to penetrate dense vegetation, revealing human-built structures underneath.

In recent years, archaeologists have turned to lasers in order to unearth previously hidden ancient civilizations.

A laser technology known as lidar — short for Light Detection and Ranging — beams tens of thousands of laser pulses per second from planes or helicopters at the ground below, penetrating through thick, deep forest canopy. That provides researchers with data to create three-dimensional maps by digitally removing the vegetation, revealing human-built structures underneath.

Researchers have found hundreds of structures in areas once thought too inhospitable for human habitation. The aerial views help them understand how far these cities and villages stretched, which archaeologists found difficult to map before lidar.

From a Maya city to complex villages deep in the Brazilian Amazon, here are six previously unknown civilizations that were discovered through state-of-the-art lidar technology.

Maya pyramidal structures in the Yucatán Peninsula

About 40 miles inside the dense vegetation of the Balamkú ecological reserve on Mexico's Yucatán Peninsula, researchers found the remains of a Maya city.

Based on pottery archaeologists found at the site, Maya people probably inhabited the city between 600 and 800 CE and perhaps earlier. Over about 123 acres, the city center contained 50-foot pyramidal structures, plazas, stone columns, and altars, according to the 2023 study.

"Architecturally, it was truly massive," archaeologist Ivan Šprajc told the BBC. "So, it's clear this must have been a politically important center."

An estimated 6 to 8 million Maya people live throughout the Americas. Thus, the culture never disappeared, but Šprajc said such archaeological finds can help scientists understand what led to "a drastic demographic decline" by the 10th century.

A hidden 2,000-year-old Maya civilization in northern Guatemala

Using laser pulses, researchers detected a 2,000-year-old Maya civilization in the Mirador-Calakmul Karst Basin region of northern Guatemala with nearly 1,000 archaeological sites.

From their topographical maps of the area, they determined that the civilization consisted of more than 417 cities, towns, and villages spread across 650 square miles. They published their findings in 2022 in the journal Ancient Mesoamerica.

The settlement had dozens of ball courts and 110 combined miles of elevated limestone-and-clay causeways that allowed ancient Mayas to travel over wetlands and between different sites.

"They're the world's first superhighway system that we have," Richard Hansen, the study's lead author, told CNN.

Nearly 500 long-lost Maya and Olmec ceremonial sites in Mexico

In 2021, researchers published a study detailing how they had used lidar to uncover 478 Mesoamerican sites they estimated were between 2,000 and 3,000 years old.

The sites are spread across a 32,800-square-mile area in the Mexican states of Tabasco and Veracruz, where the Olmec and Maya civilizations flourished.

"It was unthinkable to study an area this large until a few years ago," Takeshi Inomata, an anthropologist with the University of Arizona who co-authored the study, said in a press release at the time.

The finding helps archeologists connect the two cultures. The dates of construction and similarity of certain structures suggest that an Olmec site, San Lorenzo, provided inspiration for some Maya monuments.

61,480 previously unknown structures hidden under the dense Guatemalan jungle

In 2018, researchers explained how they used laser technology to map Petén, Guatemala, where Maya people once lived.

They discovered 61,480 long-lost roads, foundations for houses, military fortifications, and elevated causeways. They all date back to 650 and 800 CE, during the late Classic period.

The researchers estimate as many as 11 million people could have lived in the interconnected cities.

"Seen as a whole, terraces and irrigation channels, reservoirs, fortifications, and causeways reveal an astonishing amount of land modification done by the Maya over their entire landscape on a scale previously unimaginable," Francisco Estrada-Belli, an anthropologist at Tulane University and co-author of the study, said in a press release.

81 earthworks, including fortified villages and roads, deep in the Amazon rainforest

In Brazil's Mato Grasso region, archaeologists using lidar found evidence of 24 sites with 81 earthworks, which included interconnected roads and fortified villages built on mounds.

They believe the structures may have supported a complex civilization with up to 1 million people between the years 1250 and 1500 CE.

Some of the geoglyphs, as archaeologists call the sites carved into the Earth, were up to a quarter of a mile across.

Hundreds more sites may be hidden in the jungle in a "continuous string of settlements," Jonas Gregorio de Souza, the paper's lead author, told The Wall Street Journal in 2018.

"These people were combining small-scale agriculture with management of useful tree species," de Souza told The Washington Post. "So it was more a sustainable kind of land use" than current land-clearing practices.

A wide-ranging ancient civilization buried in the Bolivian Amazon

In what is now Bolivia, lidar revealed the hidden ruins of 26 Indigenous settlement sites, 11 of which were new discoveries, that thrived in the Amazon rainforest more than 600 years ago.

"Our results put to rest arguments that western Amazonia was sparsely populated in pre-Hispanic times," researchers wrote in the journal Nature.

People from the Casarabe Culture created canals, stepped platform buildings, and 72-foot conical pyramids, which occupied an area of approximately 1,700 square miles between 500 and 1,400 CE. The lidar maps helped the researchers see how the spread-out settlements fit together.

Heiko Prümers, a co-author of the study, theorized that the Casarabe may have left the settlement due to lack of rainfall. "We know that there were severe droughts in the Amazon regions several times in history," he told Smithsonian Magazine in 2022. "That might have happened to this culture as well."