Mars is the celestial body known as the "Red Planet." Its reddish appearance comes from iron oxide, also known as rust, that covers the surface and gives it a distinctive hue. Mars is the fourth planet from the Sun and is often a focal point of astronomical study due to its proximity to Earth and potential for past or present life. Its landscape features the largest volcano (Olympus Mons) and the deepest canyon (Valles Marineris) in the solar system. Ongoing missions by various space agencies aim to explore Mars more thoroughly, seeking to understand its geology and possible habitability.