https://www.vice.com/en_us/article/m7gvnp/incredible-images-show-whats-inside-the-biggest-canyon-in-the-solar-system

A Mars orbiter has captured stunning pictures of the largest canyon in the solar system, called Valles Marineris. It stretches across 2,500 miles of the red planet’s equator, a distance that is roughly equivalent to the diameter of the continental United States.

Mars Express, a European Space Agency (ESA) mission that arrived at Mars in 2003, recently imaged the deepest reaches of this epic canyon, where its slopes descend more than four miles into the Martian surface, which is five times deeper than the Grand Canyon, according to an ESA statement.