7 Places to Visit in the Solar System

Valles Marineris, Mars

Arizona’s Grand Canyon is very impressive. It’s 450 km long and about 2 km deep. However, when set next to the Valles Marineris canyon system on Mars, it is a mere ditch. Discovered in 1971 by Mariner 9, Valles Marineris stretches 4,000 km across the planet. Typical canyons are 200 km across and have walls 2–5 km deep. The center of the canyon system is a depression 600 km  across and 9 km deep. It has been speculated that Valles Marineris may be a fault system separating two continental plates. If so, Mars and Earth would be the only planets with surfaces shaped by plate tectonics.

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