Hundred mile scarp on Mercury

One of the features that distinguishes Mercury from the other planets in our solar system are the enormous scarps, or cliffs, that run for hundreds of miles across its bleak surface. They are believed to have formed when massive blocks of Mercury's crust heaved upward while the planet was still cooling and shrinking early in its development. The scarp depicted here is about two miles high (twice as high as the walls of Earth's Grand Canyon) and extends for about a hundred miles.