Tharsis Tholis towers 8 km above the surrounding terrain. Its base stretches 155 x 125 km and its caldera is about 32 x 34 km. The caldera floor has subsided by as much as 2.7 km. The image was acquired by the High Resolution Stereo Camera on Mars Express and is of an area at approximately 13°N/268°E on Mars. It combines data from HRSC’s nadir channel and one stereo channel to produce this 3D image. Stereoscopic glasses are required to see the 3D effect.