This view from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover shows a dark sand dune in the middle distance. The rover's examination of dunes on the way toward higher layers of Mount Sharp will be the first in-place study of an active sand dune anywhere other than Earth. The scene combines several images taken on Sept. 25, 2015, during the 1,115th Martian day, or sol, of Curiosity's work on Mars. The images are from Mastcam's right-eye camera, which has a telephoto lens. The view is toward south-southwest. The dunes on Curiosity's route are part of a band of dunes called "Bagnold Dunes," along the northwestern edge of Mount Sharp. The informal naming recognizes British military engineer Ralph Bagnold (1896-1990), a pioneer in the study of how winds move sand particles of dunes on Earth. The dune field is evident as a dark band in orbital images of the area inside Gale Crater were Curiosity has been active since landing in 2012, such as a traverse map at PIA20162. Dunes are larger than wind-blown ripples of sand or dust that Curiosity and other rovers have visited previously. One dune that Curiosity will investigate in coming days is as tall as a two-story building and as broad as a football field. Ripples on the surface of these Martian dunes are larger than ripples on the surfaces of sand dunes on Earth. The scene is presented with a color adjustment that approximates white balancing, to resemble how the rocks and sand would appear under daytime lighting conditions on Earth. http://photojournal.jpl.nasa.gov/catalog/PIA19928