The latest discovery made by NASA's Mars Reconnaissance Orbiter is the trail left behind by a giant boulder that rolled down a hill on the Red Planet.

NASA analysis of the rock's shadow suggests that the boulder is about 20 feet tall and 11.5 feet wide.

The trail carved out by the boulder, which landed upright, is visible from space.

"The boulder's trail down the slope is about one-third of a mile long," the space agency said. "The trail has an odd repeating pattern, suggesting the boulder could not roll straight due to its shape."

The Mars Reconnaissance Orbiter launched in 2005 on a search for evidence of water on Mars.

Next up, MRO will have a chance to monitor Mars' close encounter with Comet Siding Spring, which is expected to fly by the Red Planet in October.

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