Researchers have captured detailed images of a 5,000-year-old fortification hidden in the forests of Neamț County, Romania, using drone-mounted LiDAR technology.

LiDAR—short for light detection and ranging—works by firing rapid laser pulses toward the ground and measuring how long they take to bounce back. By calculating that return time, scientists can map elevation with remarkable precision, even through dense vegetation. The result is a high-resolution 3D model of the landscape beneath the forest canopy.

In this case, the scans revealed the outline of an ancient fortified settlement dating to the transition from the Neolithic to the Bronze Age. According to archaeologist Vasile Diaconu, the technology provided a “faithful image” of the structure and exposed details that were impossible to see on the ground because of thick plant cover.

LiDAR has previously been used to study everything from forest growth to long-lost Amazonian cities, and this latest discovery shows once again how it can transform archaeological research—especially in places where ruins are difficult to access or nearly invisible to the naked eye.