This image from NASAs Mars Odyssey shows part of the south polar cap. The cap is comprised of layers of ice and dust deposited over millions of years.

This image from NASAs Mars Odyssey shows part of Sisyphi Cavi located in Noachis Terra near the south polar cap.

This image from NASAs Mars Odyssey shows Angustus Labyrinthus. The squares formed by intersecting ridges have given the feature the informal name o...

This image from NASAs Mars Odyssey shows Gasa Crater located on the floor of a larger unnamed crater Eridania Planitia.

This image from NASAs Mars Odyssey shows Angustus Labyrinthus, a unique region near the south polar cap.

This image from NASAs Mars Odyssey is located near the south polar cap and exhibits the same layering of ice and dust.

This image from NASAs Mars Odyssey shows Cavi Angusti, located near the south polar cap.

This image from NASAs Mars Odyssey shows part of the rim of an unnamed crater in Terra Cimmeria.

This image from NASAs Mars Odyssey shows large individual dunes on the floor of Kaiser Crater.

This image from NASAs Mars Odyssey shows the floor of Matara Crater.

This image from NASAs Mars Odyssey shows part of Bonestell Crater. Bonestell Crater is a relatively young crater located in Acidalia Planitia.

This false color image from NASAs Mars Odyssey shows subtle variations of the surface not easily identified in a single band image.

This image from NASAs Mars Odyssey shows part of the floor of Pollack Crater.

This image from NASAs Mars Odyssey shows a crater located in Utopia Planitia.

This image from NASAs Mars Odyssey shows part of Ariadnes Colles. The term colles means hills or knobs.

This image from NASAs Mars Odyssey shows the relative highlands of Arabia Terra near Chryse Plainitia.

This image from NASAs Mars Odyssey shows a large trough in the north polar cap near the head of Chasma Boreale.

This image from NASAs Mars Odyssey shows a small part of the extensive volcanic plains located east of Olympus Mons.

This image from NASAs Mars Odyssey shows part of the floor of Marth Crater. Dark blue tones typically indicate basaltic sands.

This image from NASAs Mars Odyssey shows part of the floor of Pasteur Crater. The deposit in the southwest part of the floor is a fill deposit that...

This image from NASAs Mars Odyssey shows part of the floor of Herschel Crater. Sand dunes are visible at the bottom of the image.

This image from NASAs Mars Odyssey shows Mawrth Vallis cutting across the center.

This image from NASAs Mars Odyssey shows several individual dunes located in Kaiser Crater. With continued winds sand dunes will move across the su...

This image from NASAs Mars Odyssey shows a dune field on a crater floor in Terra Cimmeria. Dunes at high latitudes - near the polar caps - are affe...

This image from NASAs Mars Odyssey shows the sand deposit on the floor of Matara Crater. The deposit is thick enough to hide the underlying crater ...

This image from NASAs Mars Odyssey shows part of an unnamed crater in Noachis Terra. Several craters in the southern hemisphere contain floor fill ...

This image from NASAs Mars Odyssey shows part of the extensive volcanic flows that make up Daedalia Planum.

This image from NASAs Mars Odyssey shows sand dunes covering part of the floor of this unnamed crater in Noachis Terra.

This image from NASAs Mars Odyssey shows a section of an unnamed channel. This channel starts within Claritas Fossae and empties down hill into Ica...

This image from NASAs Mars Odyssey shows sand dunes covering part of the floor of this unnamed crater in Terra Cimmeria.

This image from NASAs Mars Odyssey shows part of the floor of Rabe Crater. The floor of Rabe Crater has undergone several surface changing events.

This image from NASAs Mars Odyssey shows a location along the margin of Ultima Lingula, where the polar cap meets the surrounding plains.

This image from NASAs Mars Odyssey shows a small portion of the extensive volcanic plains of Daedalia Planum.

This image from NASAs Mars Odyssey shows part of the floor of Spallanzani Crater. At some point after the crater was created the floor was covered ...

This image from NASAs Mars Odyssey shows an unnamed crater in Terra Cimmeria has both a sand sheet with dune forms and a multitude of dust devil tr...

This image from NASAs Mars Odyssey shows a field of sand dunes, visible on the floor of this unnamed crater. The crater is located in Terra Sirenum.

This image from NASAs Mars Odyssey shows a small portion of the immense lava plains of Daedalia Planum. These flows originated from Arsia Mons, one...

This image from NASAs Mars Odyssey shows multiple gullies dissecting the rim of an unnamed crater located in Terra Sirenum.

This image from NASAs Mars Odyssey shows part of the eastern end of Candor Chasma. The edge of the canyon is at the bottom of the image.

This image from NASAs Mars Odyssey shows a group of craters in Terra Sirenum. The apparent youngest one is the center crater with the scalloped rim.

This image from NASAs Mars Odyssey shows an isolated mountain east of Hellas Planitia. Erosion is moving material down hill towards the lower eleva...

This image from NASAs Mars Odyssey shows many large gullies dissecting the rim of this unnamed crater in Aonia Terra.

This image from NASAs Mars Odyssey shows part of an unnamed crater in Aonia Terra. The rim of this crater contains many deep gullies.

This image from NASAs Mars Odyssey shows a ring of gullies encircling the top of the depression in this crater. This unnamed crater is located in s...

This image from NASAs Mars Odyssey shows part of the inner rim of Kaiser Crater. The rim has been dissected by numerous gullies. Kaiser Crater is l...

This image from NASAs Mars Odyssey shows part of the floor of Hale Crater and the elongate axis of the central peak mountains.

This image from NASAs Mars Odyssey shows part of Claritas Fossae. The linear features (fossae) are flaults.

This image from NASAs Mars Odyssey shows a portion of Noachis Terra to the northeast of Argyre Planitia.

This image from NASAs Mars Odyssey shows part of the eastern side of Maunder Crater.

This image from NASAs Mars Odyssey shows a small part of the south polar cap. The layers record the seasonal deposition of dust and ice over the co...