This image from NASAs Mars Odyssey shows a small section of Hydaspis Chaos, one of many regions of chaos in Margaritifer Terra.

This image from NASAs Mars Odyssey shows a small section of Cydonia Colles, a group of hills located in southeastern Acidalia Planitia.

This image from NASAs Mars Odyssey shows several craters in northwestern Arabia Terra.

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

This image from NASAs Mars Odyssey shows several craters located in Terra Cimmeria.

This image from NASAs Mars Odyssey shows part of Nili Fossae. The linear depressions crossing the center of the image are graben.

This image from NASAs Mars Odyssey shows a cross section of Hebes Chasma. Hebes Chasma is a closed basin located north of Valles Marineris.

This image from NASAs Mars Odyssey shows part of the floor of an unnamed crater located in Arabia Terra, near the boundary with Acidalia Planitia.

This image from NASAs Mars Odyssey shows sand dunes on the floor of an unnamed crater in Terra Cimmeria. Dark blue in this filter combination indic...

This image from NASAs Mars Odyssey shows a small section of Nili Fossae. The linear depression at the top of the image is one of the Nili Fossae gr...

This image from NASAs Mars Odyssey shows a crater in Arabia Terra. Dark blue in this filter combination indicates basaltic sand.

This image from NASAs Mars Odyssey shows sand sheets in two unnamed craters located in Noachis Terra.

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

This image from NASAs Mars Odyssey shows a small section of Mangala Valles. Mangala Valles is a complex channel more than 900km long (560 miles).

This image from NASAs Mars Odyssey shows an unnamed crater located on the margin of the south polar cap.

This image from NASAs Mars Odyssey shows Promethei Chasma, part of the South Pole.

This image from NASAs Mars Odyssey shows Angustus Labyrinthus. The squares formed by intersecting ridges earned the feature the informal name of th...

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

This image from NASAs Mars Odyssey shows part of McMurdo Crater. Located on the margin of the south polar cap, the layering of the ice is visible a...

This image from NASAs Mars Odyssey crosses both Ophir Chasma and Candor Chasma. Layered and eroded material covers the floors of both chasmata. Bot...

This image from NASAs Mars Odyssey shows Claritas Fossae, a graben filled highland located between the lava plains of Daedalia Planum and Solis Pla...

This image from NASAs Mars Odyssey shows Claritas Fossae, a graben filled highland located between the lava plains of Daedalia Planum and Solis Pla...

This image from NASAs Mars Odyssey shows an unusual layer of smooth material covers the flanks of the volcano Peneus Patera just south of the Hella...

This image from NASAs Mars Odyssey shows an unusual layer of smooth material covering the flanks of the volcano Peneus Patera just south of the Hel...

This image from NASAs Mars Odyssey shows part of Richardson Crater. A large sand sheets covers the floor of the crater.

This image from NASAs Mars Odyssey shows a linear depression, part of Sirenum Fossae. Depressions of this type are called graben, which form by the...

This image from NASAs Mars Odyssey shows part of Richardson Crater. A large sand sheet covers most of the floor of the crater.

This image from NASAs Mars Odyssey shows a small portion of the immense lava flows that originated from Arsia Mons.

This image from NASAs Mars Odyssey shows part of the south polar cap. Millions of years of alternating seasons have created the south polar cap.

This image from NASAs Mars Odyssey shows part of the south polar cap. The cap was created over millions of years with deposition of ice and dust du...

This image from NASAs Mars Odyssey shows the summit caldera of Arsia Mons. Several small volcanic vents are visible on the caldera floor.

This image from NASAs Mars Odyssey shows linear depressions, part of Sirenum Fossae.

This image from NASAs Mars Odyssey shows part of the surface of the south polar cap.

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 part of Gorgonum Chaos. Chaotic regions form when groundwater escapes to the surface, undermining it and c...

This image from NASAs Mars Odyssey shows a linear depression, part of Sirenum Fossae.

This image from NASAs Mars Odyssey shows a small portion of the immense lava flows that originated from Arsia Mons.

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

This image from NASAs Mars Odyssey shows a portion of Niger Vallis. The channel is 333 km (207 miles) long.

This image from NASAs Mars Odyssey shows a field on dunes on the floor of an unnamed crater in southern Terra Sirenum.

This image from NASAs Mars Odyssey shows a small portion of the immense lava flows that originated from Arsia Mons.

This image from NASAs Mars Odyssey shows the delta deposit on the floor of Eberswalde Crater.

This image from NASAs Mars Odyssey shows a small section of Nirgal Valles. Located in Noachis Terra, Nirgal Valles is 610km long (379 miles).

This image from NASAs Mars Odyssey shows dunes, located on the complex floor of Rabe Crater.

This image from NASAs Mars Odyssey shows Cavi Angusti, located near the south polar cap, consists of large irregular steep-sided depressions termed...

This image from NASAs Mars Odyssey shows three craters in Terra Cimmeria.

This image from NASAs Mars Odyssey shows a small portion of the immense lava flows that originated from Arsia Mons.

This image from NASAs Mars Odyssey shows part of Richardson Crater and an unnamed crater.

This image from NASAs Mars Odyssey shows a short section of Reull Vallis. Reull Vallis starts in Promethei Terra and empties into Hellas Plainitia.

This image from NASAs Mars Odyssey shows a small portion of the immense lava flows that originated from Arsia Mons.