Mars Index - Top Ten MER Images - Top Raw Images
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In the lower right corner of this black-and-white image are the top faces of two bumpy, nodular rocks. In the lower left corner are the stacked, flat tiers of a layered rock, arranged atop each other like a set of stairs. Elsewhere, the surface is covered by fine-grained sand and a few small chips of rocks.
Stair-stepped Stones and Rumply Rock
If you thought "a rock was a rock was a rock," check out these strange, alien-shaped rocks.

Image Credit: NASA/JPL/Cornell