Only a handful of ancient Mayan temples rise above a dense jungle of trees in Guatemala. But what's obscured by the thick foliage, revealed for the first time, is evidence of a sprawling civilization to rival ancient Greece or China. Using LiDAR technology (Light Detection And Ranging), which measures wavelengths from laser pulses aimed at the ground, scientists digitally removed the jungle to reveal more than 60,000 previously unknown Mayan structures like palaces, fortifications, farms, irrigation systems, and raised highways connecting nearly all ancient cities across 800 square miles in northern Guatemala, report Live Science and National Geographic. "We'll need 100 years to go through all [the data] and really understand what we're seeing," says researcher Francisco Estrada-Belli. But already it's apparent that the civilization has been "grossly underestimated," says archaeologist Thomas Garrison.
The new data show a civilization twice the size of medieval England at its peak 1,200 years ago. And though population estimates previously hovered around 5 million, expansive irrigation and terracing systems and wide highways indicate there might've been "10 to 15 million people there—including many living in low-lying, swampy areas that many of us had thought uninhabitable," Estrada-Belli says. Walls, fortresses, and ramparts also suggest war was "large-scale and systematic" and "endured over many years" not just "toward the end of the civilization," says Garrison. One of the coolest discoveries, however, was a 100-foot pyramid in the heart of the city of Tikal, which was previously assumed to be a small mountain, reports Reuters. More discoveries are likely to be made as scientists plan to map 5,000 square miles of Guatemala's lowlands during the ongoing project. (The Maya parried one collapse before the fatal blow.)