LiDAR stands for ‘laser imaging, detection and ranging’. It helps archaeologists ‘see’ subtle changes in the height of the modern ground surface by bouncing light from the LiDAR instrument to the ground, then measuring the time that the light takes to return to the instrument’s detector. The longer it takes, the longer the distance between the detector and the ground. LiDAR can be used to create detailed topographic maps, and to pick out slight changes in height caused by buried archaeological features like roads, boundaries and building foundations that would otherwise be too subtle to see with the naked eye.