Nomadic Dunes of Mars

(Speaking of nomadic dunes, above are three fantastic pairs of before and after images offering evidence that Martian dunes aren't all frozen or heavily encrusted but are actively migrating, displaced and re-sculpted by extraterrestrial winds. Image by Credit: NASA/JPL-Caltech/University of Arizona/International Research School of Planetary Sciences. See also Tornado Alleys of Mars, Mars Weather Report and Vortex Mars.)