This is the largest volcano in our solar system, as far as anybody knows — the mighty Olympus Mons, as snapped by the ESA Mars Express mission’s HRSC, or High-Resolution Stereo Camera. The mission’s goal is to create very detailed 3D maps of the surface of Mars, which is obviously pretty useful to anyone who wants to land anything there, as well as maps of the chemical composition of the atmosphere, which is obviously pretty useful to anyone who wants to build anything there (or even try to breathe there), and some detailed looks at the little Martian moons of Deimos and Phobos, which is… nice. They’ve got videos on that link, and studies of ice, and all sorts of cool stuff.
North is off to the left. This mountain is about 16 miles high and as big around as Arizona. Not the Grand Canyon, but the whole state the Grand Canyon is in. If the crater erupted in Warsaw, it would cover essentially all of Poland. Another fun fact: It might not be dormant. Just “quiescent.” Waiting, in other words, for another big show.
I found the image on Andrea Luck’s photostream on Flickr, which is full of space art. Credit: ESA/DLR/FUBerlin/AndreaLuck CC BY.