1. Sunset on Mars

"On May 19, 2005, NASA's Mars Exploration Rover Spirit captured this stunning view as the Sun sank below the rim of Gusev crater on Mars. This Panoramic Camera mosaic was taken around 6:07 in the evening of the rover's 489th Martian day, or sol."

2. Mars' Shifting Sands

"As spring now dawns on the Northern Hemisphere of Mars, sand dunes near the pole, as pictured above, are beginning to thaw. The carbon dioxide and water ice actually sublime in the thin atmosphere directly to gas. Thinner regions of ice typically defrost first revealing sand whose darkness soaks in sunlight and accelerates the thaw. The process might even involve sandy jets exploding through the thinning ice. By summer, spots will expand to encompass the entire dunes. The Martian North Pole is ringed by many similar fields of barchan sand dunes, whose strange, smooth arcs are shaped by persistent Martian winds.

3. Proctor Crater, Mars

On Feb. 9, 2009, "This view from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter is of the Proctor Crater. The relatively bright, small ridges are ripples. From their study on Earth, and close-up examination by the MER rovers (roving elsewhere on Mars), scientists surmise that the ripples are composed of fine sand (less than 200 microns in diameter) or fine sand coated with coarser sand and granules.

4. Tattooed Mars

"Originally released Aug. 1, 2007, this image is of Mars' Russell Crater dune field, which is covered seasonally by carbon dioxide frost. This image shows the dune field after the frost has evaporated from solid to gas, with just a few patches remaining of the bright seasonal frost. Numerous dark dust devil tracks can be seen meandering across the dunes."

5. Fountain

"Originally released May 30, 2007, this image is centered on a small cone on the side of one of Mars' giant shield volcanoes. The cone shows some layers of hard rock but most of it is made of relatively soft material. This appears to be an example of a 'cinder' cone composed of pieces of lava thrown into the air during a small volcanic eruption."

6. A Mosaic From Mars Odyssey

"Colors indicate infrared emission signatures in this mosaic from NASA's Mars Odyssey orbiter, showing a region of troughs named Nili Fossae. Analysis from Odyssey's Thermal Emission Imaging System suggests that a deposit rich in the mineral olivine is about four times larger than earlier thought. The olivine-rich exposures appear magenta to purple-blue in this color-coding.

7. Blue Like Mars

On April 13, 2010,"This image shows the west-facing side of an impact crater in the mid-latitudes of Mars' northern hemisphere. Like many mid-latitude Martian craters, this one has gullies along its walls that are composed of alcoves, channels and debris aprons. The origins of these gullies have been the subject of much debate; they could have been formed by flowing water, liquid carbon dioxide or dry granular flows.

8. Dunes of Mars

"Dunes of sand-sized materials have been trapped on the floors of many Martian craters. This is one example, from a crater in Noachis Terra, west of the giant Hellas impact basin. The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter captured this view on Dec. 28, 2009."

9. Cape Verde, Mars

"A promontory nicknamed Cape Verde can be seen jutting out from the walls of Victoria Crater in this false-color image taken by the panoramic camera on NASA's Mars Exploration Rover Opportunity. The rover took this picture on Martian day, or sol, 1329 (Oct. 20, 2007), more than a month after it began descending down the crater walls -- and just 9 sols shy of its second Martian birthday on sol 1338 (Oct. 29, 2007). Opportunity landed on the Red Planet on Jan. 25, 2004. That's nearly four years ago on Earth, but only two on Mars because Mars takes longer to travel around the sun than Earth. One Martian year equals 687 Earth days."

10. Mars' Valles Marineris

“Global mosaic of 102 Viking 1 Orbiter images of Mars taken on orbit 1,334, 22 February 1980. The images are projected into point perspective, representing what a viewer would see from a spacecraft at an altitude of 2,500 km. At center is Valles Marineris, over 3000 km long and up to 8 km deep. Note the channels running up (north) from the central and eastern portions of Valles Marineris to the dark area, Acidalic Planitia, at upper right. At left are the three Tharsis volcanoes and to the south is ancient, heavily impacted terrain.”