In this VIS Contextual Image (or "CTX" frame), taken by the NASA - Mars Odyssey Orbiter on April, 21st, 2016, and during its 63.676th orbit around the Red Planet, we can see (a small section of) the interior of Milankovic Crater (an Impact Crater located in the Diacria Quadrangle of Mars, having a diameter of approx. 118,4 Km, such as about 73,5264 miles. It is centered - roughly - at 54,7° North Latitude and 146,7° West Longitude).
The Dark Dunes visible in the center of the image are in the Pit located at the Summit of the Crater's Peak. On the other hand, the small (but still Dark) Dunes located near the bottom of the image are on the Floor of the Crater itself. As a matter of fact, many medium-sized Impact Craters of Mars have/show (a) Central Peak (or Peaks) with a Summit Pit and, most likely (but we have - so far - no way to know if that theory is actually true) both the Peak/s and Pit/s formed at the time when the Impact occurred.
Latitude (centered): 54,3932° North
Longitude (centered): 213,5370° East
This picture (which is an Original Mars Odyssey Orbiter b/w and Map Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 20628) has been additionally processed, magnified to aid the visibility of the details, extra-contrast enhanced and sharpened, Gamma corrected and then colorized in Absolute Natural Colors (such as the colors that a normal 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.