In this VIS image, taken by the NASA - Mars Odyssey Orbiter on December, 1st, 2013, and during its 53.076th orbit around the Red Planet, we can see the Erg (---> Sea/Ocean of Dunes) that surrounds the North Polar Cap of Mars. It is Springtime, now, at the North Pole (---> in the Northern Hemisphere of Mars) and the Dunes are starting to lose their Frost cover. As the season continues towards Summer, the Dunes will appear darker and darker, as the Frost sublimates.
The bright (and round, as we have found out using other frames) spot visible on the upper side of the picture should be just a patch of Permanent Ice which is located (and therefore, somehow, protected) inside a relatively shallow Depression of the Surface - possibly (but we have no way to be sure), an almost rimless and very old Impact Crater. You can take a look, if you wish to get a few more visual information about this area, at the APOD of April, 1st, 2013.
Latitude (centered): 80,267° North
Longitude (centered): 157,439° East
This image (which is an Original Mars Odyssey Orbiter b/w and Map-Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 17865) has been additionally processed, magnified, contrast enhanced, Gamma corrected and then colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Mars Odyssey Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.