Along with tall mountains, Mars' terrain has vast, deep canyons. The Valles Marineris system of canyons is more than 2,500 miles long, 120 miles wide, and in places as deep as 23,000 feet.
October 28, 2013 1:11 PM PDT
Photo by: ESA / DLR / FU Berlin (G. Neukum)
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