Mars

Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, after Mercury. Mars is named after the Roman god of war and is often referred to as the, "Red Planet". This refers to the effect of the iron oxide present on Mars' surface, which gives it a reddish appearance, standing out among the objects in space visible to the naked eye. Mars is a terrestrial planet with a thin atmosphere, having surface features similar to both of the impact craters of the Moon and the valleys and deserts on Earth.

Mars is the site of Olympus Mons, the largest volcano and highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System.