Steep Cliffs on Mars

Vertical cliffs of nearly two kilometers occur near the North Pole of Mars.
Also visible in the above image of the Martian North Polar Cap are red
areas of rock and sand, white areas of ice, and dark areas of unknown
composition but hypothesized to be volcanic ash. The cliffs are thought
to border volcanic caldera. Although the sheer drop of the Martian cliffs
is extreme, the drop is not as deep as other areas in our Solar System,
including the 3.4-kilometer depth of Colca Canyon on Earth and the 20
kilometer depth of Verona Rupes on Uranus' moon Miranda. The above ,
image digitally reconstructed into a perspective view, was taken by
the High Resolution Stereo Camera on board the ESA's robotic Mars
Express spacecraft currently orbiting Mars.