Carbon dioxide ice landscape on Mars, satellite image. Taken during winter at the South Pole of Mars, this image shows araneiform terrain, where spider-like forms are emerging from the carbon dioxide ice as it melts. The darkness of the features are due to darker dust that is deposited at these seasonal vents as they form and release carbon dioxide gas. These observations were made by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter (MRO) spacecraft. Image obtained on 13 May 2018.