A stain visible on the slopes of the 'Butterfly' crater in Hesperia Planum. Click for larger image.
This is an image from the ESA mars Express.
The HRSC on board ESA's Mars Express spacecraft obtained this colour image on 5 May 2004 during orbit 368 with a ground resolution of approximately 16.7 metres per pixel. The scene shows the region of Hesperia Planum, at approximately 35.3° South and 118.7° East.