Mars carries the name of the Roman god of war and is often called the " Red Planet "
Olympus Mons , the largest volcano and highest known mountain on any Solar System planet , and Valles Marineris , one of the largest canyons in the Solar System , are on Mars .
Mars has been explored by several uncrewed spacecraft .
Mars can easily be seen from Earth with the naked eye , as can its reddish coloring .