English: This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express spacecraft, shows the regions of Granicus Valles and Tinjar Valles, which may have been formed partly through the action of subsurface water, due to a process known as sapping. The HRSC obtained these images on 14 February 2005 during orbit 1383 at a ground resolution of approximately 23.7 metres per pixel. The images have been rotated 90 degrees counter-clockwise, so that North is to the left. Both channel systems evolve from a single main channel entering the image scene from southeast (upper right), exhibiting an approximate width of 3 km and extending 300 m below the surrounding terrain at maximum.