LIDAR

http://blog.lidarnews.com/lidar-as-art-to-honor-911-tragedy

LIDAR (light detection and ranging) uses light to measure to distances related to a target such as distance to the object among other properties of the target. This often done using pulses from a laser and can be applied to multiple sciences including geology and archaeology. The above is a LIDAR of the site where the twin towers were before the attack on 9/11.