Layers of Red Cliffs on Mars. The northern ice cap on Mars is nearly divided into two by a huge division named Chasma Boreale. No similar formation occurs on Earth. Pictured above, several dusty layers leading into this deep chasm are visible. Cliff faces, mostly facing left but still partly visible from above, appear dramatically red. The light areas are likely water ice.
Mars's biggest outflow channels stretch for hundreds of kilometers across the southern circum-Chryse region. Dunes ripple across the plains near the mouth of this channel. The ancient channels were likely carved by gushing torrents of water, each hundreds to thousands of times larger than the Mississippi. These massive rivers may have erupted from underground sources, suggesting that shallow groundwater reservoirs were once relatively common in Mars's upper crust. | NASA/JPL/UofArizona
They might look like trees on Mars, but they're not. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. The above image was taken in 2008 April near the North Pole of Mars. At that time, dark sand on the interior of Martian sand dunes became more and more visible as the spring Sun melted the lighter carbon dioxide ice.
Collapse in Hebes Chasma on Mars. The above image, taken by the robotic Mars Express spacecraft currently orbiting Mars, shows great details of the chasm and the unusual horseshoe shaped indentation in the central mesa. Material from the mesa appears to have flowed onto the floor of the chasm, while a possible dark layer appears to have pooled like ink on a downslope landing.
This image of a circular depression on the surface of Mars was acquired on Jan. 5, 2015 by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter (MRO). The spacecraft has been orbiting Mars since March 2006 and completed its 40,000th orbit around Mars on Feb. 7, 2015.