The Asteroid Belt is a region of space between the orbits of Mars and Jupiter where potentially millions of asteroids orbit.
The region between the orbits of Mars and Jupiter contains potentially millions of asteroids made up of rock, metal, and ice. However, most of the asteroids in the main belt are probably smaller than 1 km in diameter.
The largest body in this region is Ceres, a dwarf planet that is about 940 km across. It makes up about 1/3 of the mass of the Asteroid Belt. Ceres was also the first object in the Asteroid Belt to be discovered. Giuseppe Piazzi found it on 1 January 1801. At the time it was considered a planet, until more objects in the region were discovered. They were then called "asteroids" by William Herschel in 1802.