Mars carries a scar so vast that Earth has nothing to match it. Valles Marineris, a system of interconnected canyons running along the Martian equator, stretches about 2,500 miles from end to end.

Mars today is a frozen, dusty desert. But if you look deep inside Valles Marineris, the largest canyon system on Mars and in the Solar System, you find familiar landforms. They resemble river deltas, ...

Add Yahoo as a preferred source to see more of our stories on Google. A mesmerizing new video from the European Space Agency lets you glide over Mars's rugged surface, revealing a sprawling 800-mile ...

Mars has its own version of the Grand Canyon, and scientists have learned this dramatic feature is home to "significant amounts of water" after a discovery made by an orbiter circling the red planet, ...