This might seem like some kind of psychedelic artwork—but you're actually looking a hundreds of individual lava flows, frozen in time on the side of Olympus Mons on Mars.
This leading color image of the solar system's largest volcano, taken earlier this year by the European Space Agency’s Mars Express, shows the transition region between the towering heights of the volcano and the flat lava plains at the base.
You can make out an intricate series of narrow, overlapping lava flows which reveal the volcano's incredibly active past. You can make out the flows that stopped before they reach the flat plain at the base of the mountain (blue in this image)—they're the ones with rounded tongues, formed as the lava cooled and crept to a stop. [ESA]
Image by ESA