Among the countless monuments of world cultural heritage of Greece, ancient theaters are studied in this work from the engineer’s point of view. With the help of aerial and satellite archeology, and of bibliographic research, their positions were determined and their size characteristics were calculated. Images of three different Unmanned Aerial Vehicles, UAV (Remote Control Helicopter, Balloon, Drone), Ikonos-2 satellite images, and images from Google Earth were used. Remote sensing image processing and its products are also presented, such as Digital Surface Models (DSMs) and the ortho images of the ancient theaters with spatial resolutions ranging from 1cm to 2.5m, referenced to the Greek Geodetic Reference System of 1987 (GGRS 87). In addition, information and conclusions were made through Geographical Information Systems (GIS) about the macroscopic characteristics of ancient theaters, such as orientation (the main orientation of the theaters is from 90ο to 270ο, while for the construction of the theaters the average direction of the winds, which should be lateral, was taken very seriously,), area (the area of the koilon of ancient Greek theaters ranges from 56m2 to 7,640m2), altitude (the altitudes of the ancient Greek theaters range from 6m to 870m), distances from the coastline (ranges from 11m to 42,559m), visibility (ranges from 0.63% to 100%), etc.