This image captured by NASA's 2001 Mars Odyssey spacecraft shows part of the large dune field called Olympia Undae. There are hills in this region, and the dunes are concentrated in the lower elevations.
At Mars' North Pole is a dome of icy layers ranging up to 2 kilometers thick, roughly analogous to the Earth's ice caps in Greenland or Antarctica. This image is from NASA's Mars Reconnaissance Orbiter.
Eridania Basin, located at the head of Ma'adim Vallis, has mounting geomorphic and spectral evidence that it may have been the site of an ancient inland sea. This image is from NASA's Mars Reconnaissance Orbiter.
NASA's Curiosity Mars rover used the Mars Hand Lens Imager (MAHLI) camera on its arm to catch the first images of sparks produced by the rover's laser being shot at a rock on Mars. The left image is from before the laser zapped this rock, called 'Nova'.
Curiosity's ChemCam Examines Mars Rock Target 'Nova'
A Martian target rock called 'Nova,' shown here, displayed an increasing concentration of aluminum as a series of laser shots from NASA's Curiosity Mars rover penetrated through dust on the rock's surface.
This rock encountered by NASA's Curiosity Mars rover is an iron meteorite called 'Lebanon,' similar in shape and luster to iron meteorites found on Mars by the previous generation of rovers, Spirit and Opportunity.
This image from NASA's 2001 Mars Odyssey spacecraft shows more north polar dunes. If you compare multiple dune images, you will see that the dunes can take different forms and cover different amounts of the plains.
This pair of images covers one of many sites on Mars where researchers use the HiRISE camera on NASA's Mars Reconnaissance Orbiter to study changes in gullies on slopes. Changes are visible in deposits near the lower end of this gully.
The cliff face in this image captured by NASA's 2001 Mars Odyssey spacecraft is called Rupes Tenius (rupes = scarp). The polar cap is the higher region to the left and the plains are located on the right side of the image.