'Monolith' Object on Mars? You Could Call It That

From the article: "When your resolution is too low to fully resolve an object, it tends to look rectangular because the pixels in the image are squares. Any curve will look like a series of straight lines if you reduce your resolution enough."

Like the "face," this is most likely the combination of the right angle and shadowing, low resolution, and our hopes of finding something earth-shattering on an alien planet.

Tl;dr: it's a smallish squarish rock.

There is, however, a genuinely impressive monolith on Mars' moon Phobos. It's about the size of a 30-story building.

http://en.wikipedia.org/wiki/Phobos_monolith

TLDR it's a rock.

A Monolith on Mars?

Damn Fedex - it was supposed to be delivered to Jupiter.