Sand dunes often accumulate in the floors of craters. In this region of Lyot Crater, NASA's Mars Reconnaissance Orbiter (MRO) shows a field of classic barchan dunes on Jan. 24, 2018. Just to the south of the group of barchan dunes is one large dune with a more complex structure. This particular dune, appearing like turquoise blue in enhanced color, is made of finer material and/or has a different composition than the surrounding. North is up. Credit: NASA/JPL-Caltech/Univ. of Arizona #nasa #highrise #mars #craters #marsreconnaissanceorbiter #dunes #solarsystem #exploration #science #technology #spaceistheplace