There are many hills about 1 kilometer high in Juventae Chasma, which is located north of the main Valles Marineris canyon system. The floor of the canyon is covered by a sea of sand, but the hills rise above the sand.
A few adventuresome sand dunes have slowly climbed up on the hills, like that near the upper left of the enhanced-color cutout. The color diversity here is exceptional, due to varying mineral compositions and good exposures. [More at link]