- Valles Marineris (/‘v�l?s m�r?’n??r?s/; Latin for Mariner Valleys, named after the Mariner 9 Mars orbiter of 1971�72 which discovered it) is a system of canyons that runs along the Martian surface east of the Tharsis region. At more than 4,000 km (2,500 mi) long, 200 km (120 mi) wide and up to 7 km (23,000 ft) deep, Valles Marineris is the largest canyon in the Solar System.
