Tharsis Tholus towers almost 5 miles (8 km) above the surrounding terrain of Mars. Its base stretches 96 x 77 miles (155 x 125 km), and is unusual in its battered condition. The main feature of Tharsis Tholus is the caldera at its centre. It has an almost circular outline, about 20 x 21 miles (32 x 34 km), and is ringed by faults where the caldera floor has subsided by as much as 1.6 miles (2.7 km). The image was created using a Digital Terrain Model (DTM) obtained data taken by the High Resolution Stereo Camera on ESA's Mars Express spacecraft during four orbits of Mars between October 28 and November 13, 2004. Elevation data from the DTM is color-coded: Purple indicates the lowest lying regions and beige the highest.