Realistic perspective views of the Martian surface can be generated from data acquired by the stereo and colour channels of the High Resolution Stereo Camera (HRSC) on ESA's Mars Express spacecraft, which are oriented at an angle with respect to the planet’s surface.
A valley-shaped depression can be seen in the centre of the image, which has been partly filled with material that has presumably been transported there from the hills in the higher Phlegra Montes. Flow patterns can be seen on the surface of the valley floor, indicating that this material had viscoplastic flow properties. The flow patterns, which are aligned in parallel, bear a strong similarity to the surfaces of 'rock glaciers' on Earth. Such bodies of ice are interspersed with boulders and rocky debris and occur on Earth primarily in regions of permafrost on high mountain ranges or at polar latitudes.
As a joint undertaking by DLR, ESA and FU Berlin, the Mars Express HRSC images are published under a Creative Commons licence since December 2014: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO. This licence will also apply to all HRSC images released to date.