Edited Mars Reconnaissance Orbiter image of a putative paleolake, where "putative" means "probably" and "paleolake" means petrified lake (well, maybe).

Edited Mars Reconnaissance Orbiter image of mounds on Mars' north polar region seen obliquely.

Edited Mars Reconnaissance Orbiter image of sand dunes on Mars in Chasma Boreale. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of Canberra Crater on Mars.

Edited Mars Reconnaissance Orbiter image of a plateau on Mars.

Edited Mars Reconnaissance Orbiter image of linear, light-toned sand dunes.

Edited Mars Reconnaissance Orbiter image of a pit on Mars. Cropped, processing variant that lets you see the bottom.

Edited Mars Reconnaissance Orbiter image of snowy sand dunes on Mars.

Edited Mars Reconnaissance Orbiter image of Martian sand dunes being tracked for the USGS. Color/processing variant.

Edited Mars Reconnaissance Orbiter of sedimentary rock layers in Terby Crater on Mars.

Edited Mars Reconnaissance Orbiter image of a layered mound with sand dunes in Juventae Chasma. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of dark and light toned terrain in Terra Sabaea. Color variant.

Edited Mars Reconnaissance Orbiter image of dark fans in east Coprates Montes.

Edited Mars Reconnaissance Orbiter image of an unfilled circular depression on Mars.

Edited Mars Reconnaissance Orbiter image of layers or rock peeking out from sand dunes in Danielson Crater on Mars. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of dark objects in Candor Chasma, perhaps volcanic in origin.

Edited Mars Reconnaissance Orbiter image of a mid-latitude pit in the surface of Mars. (It looks like a mound, but is a depression, not a hill.)

Edited Mars Reconnaissance Orbiter image of Schaeberle Crater.

NASA’s Jet Propulsion Laboratory published a perplexing photo yesterday along with the question, “What is this enigmatic landform?” The photo shows a large, 1.2 mile wide, circular structure (the lab rats think it’s a a giant mutant Martian amoeba) surrounded by a sea of smooth-looking lava flows. NASA scientists believe the mound may be lava that has pushed up beneath the lava flow.

reekoscience.com/science-news/space/nasa-spots-odd-circul...

Edited Mars Reconnaissance Orbiter image of an oblong impact crater in Terra Cimmeria.

Edited Mars Reconnaissance Orbiter image (from its Flickr photostream) of sand dunes marching down shallow valleys.

Edited Mars Reconnaissance Orbiter image of sand dunes in Hyperborei Cavi. (I love Martian names.) Processing variant.

Edited Mars Reconnaissance Orbiter image of odd patterns in Eschus Chasma.

Edited Mars Reconnaissance Orbiter image of a shallow valley turning into an inverted channel on Mars. Color variant.

Edited Mars Reconnaissance Orbiter image of layers or rock peeking out from sand dunes in Danielson Crater on Mars. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of a collapsed channel margin (edge). Color variant.

Edited Mars Reconnaissance Orbiter image of the north Hellas Region.

Edited Mars Reconnaissance Orbiter image of shallow valleys in Tyrrhena Terra on Mars. (Slight) color/processing variant.

Edited Mars Reconnaissance Orbiter image of sand dunes on Mars in the shape of upside-down Ts. (Or perhaps the image is upside-down.)

Edited Mars Reconnaissance Orbiter image of a fissure cutting across the bottom of a crater floor on Mars. Color variant.

Edited Mars Reconnaissance Orbiter image of a subtly-colored region of Mars.

Animated GIF (created by NASA) from Mars Reconnaissance Orbiter images of the results of an avalanche of ice blocks from Mars' north polar cap over six Martian years.

Edited Mars Reconnaissance Orbiter image of Martian sand dunes being tracked for the USGS.

Edited Mars Reconnaissance Orbiter image of "dune convoys in West Olympia Undae. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of sand dunes named La Jolla.

Edited Mars Reconnaissance Orbiter image of deposits of sediment in Ladon Basin on Mars. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of pits and sand dunes in Hale Crater. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of dark and light toned terrain in Terra Sabaea.

Edited Mars Reconnaissance Orbiter image of a crater south of Mawrth Vallis. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of large cracks in the surface of Mars in Cerberus Fossae. Color variant.

Edited Mars Reconnaissance Orbiter image of the floor of Roddy Crater on Mars. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of rocky deposits on the floor of Briault Crater on Mars.

Edited Mars Reconnaissance Orbiter image looking for frost on the rim of Corozal Crater - it's thought that frost may play a roll in the creation of gullies.

Edited Mars Reconnaissance Orbiter image of moraine-like features on mounds in Hellas Montes. Color variant.

Edited Mars Reconnaissance Orbiter image of a part of Kasei Valles on Mars.

Edited Mars Reconnaissance Orbiter image of rock falls (into a large fissure) in Cerberus Fossae on Mars. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of tracks over sand dunes in Charlier Crater on Mars.

Edited Mars Reconnaissance Orbiter image of an oblong impact crater in Terra Cimmeria. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of gullies and slopes being monitored for changes. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of exposed layers in deposits in the far north of Mars.