The largest canyon in the solar system.
Valles Marineris is a colossal canyon system stretching more than 4,000 km along the Martian equator — nearly a fifth of the way around the planet — and plunging up to 7 km deep. Laid over Earth, it would reach from Los Angeles to New York.
Claim your plot here →Unlike Earth's Grand Canyon, which the Colorado River slowly carved out, Valles Marineris was torn open by tectonic stress. As the enormous Tharsis volcanic bulge swelled next door, it stretched and cracked the crust until it split apart into this vast rift.
Over billions of years, landslides, collapsing walls and possibly ancient water widened the gash into the canyon we see today — deep enough to swallow the tallest mountains on Earth with room to spare.
About 10× longer, 4× deeper and far wider — the Grand Canyon would fit inside one small side-branch.
Long enough to stretch clear across the continental US, coast to coast.
Up to 7 km deep — you could stack Mount Everest's lower half inside it.