The Curiosity Rover's planet is MARS, which is the fourth planet from the Sun and the second smallest planet in the Solar System. It is known for its red-orange hue and is often referred to as the 'Red Planet'. MARS is home to the largest mountain in the Solar System, Olympus Mons, and the Valles Marineris, the largest canyon. It is believed to have once had liquid water on its surface, and is now a cold and dry desert.