Valles Marineris – The Grand Canyon of Mars

Valles Marineris – The Grand Canyon of Mars
October 22, 2012

A digital terrain model of a portion of Mars’ Valles Marineris, the largest canyon in the Solar System. Credit: ESA/DLR/FU Berlin (G. Neukum)

Wikipedia:
Valles Marineris (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 long, 200 km wide and up to 7 km deep, the Valles Marineris rift system is one of the larger canyons of the Solar System, surpassed only by the rift valleys of Earth and (in length only) by Baltis Vallis on Venus.

Below is a video released by JPL in 2006 showing a virtual fly-through of Valles Marineris:
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