NASA's Mars rover recently sent back stunning pictures of active dunes on Mars.

NASA's Curiosity rover recently visited an area with active sand dunes on Mars. And even sent back pictures. 
One image from inside Gale Crater shows dozens of dark dunes rippling with sandy veins and almost stylized-looking peaks and troughs.  Curiosity is presently visiting the Bagnold Dunes—the sands of which are estimated to migrate nearly three feet per Earth year. 
Nathan Bridges, with Johns Hopkins University's Applied Physics Laboratory, noted, "The