Valles Marineris is a massive canyon system that runs along the Martian equator. At over 4,000 km long, 200 km wide and about 7 km deep, it is larger than any of Earth's canyons, and is the largest...
The Valles Marineris is the largest complex canyon on mars big enough to stretch across the united states, it was revealed by the Mariner 9 space craft.
Valles Marineris was formed by tectonic processes on Mars. It was formed from east to west, in a direction prograde in respect to the planets rotation.