Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Valles Marineris (Latin for Mariner Valleys, named after the Mariner 9 Mars orbiter of 1971 72 which discovered it) is a system that runs along the Martian surface east of the Tharsis region. At more than 4,000 km long, 200 km wide and up to 7 km deep, the Valles Marineris rift system is larger than any of Earth''s largest canyons, and is the largest known canyon in the solar system. Valles Marineris is located along the equator of Mars, on the east side of the Tharsis Bulge, and stretches for nearly a quarter of the planet''s circumference.