Pluto was once considered the ninth planet in our solar system, but in 2006, the International Astronomical Union (IAU) reclassified it as a dwarf planet. This is because it doesn't meet all the criteria for a full-fledged planet, namely:

* It hasn't cleared its neighborhood of other objects. Pluto shares its orbital space with other icy bodies in the Kuiper Belt.

Here are some other examples of dwarf planets:

* Eris: Larger than Pluto, Eris is also located in the Kuiper Belt.

* Makemake: Another Kuiper Belt object, Makemake is slightly smaller than Pluto.

* Haumea: A very elongated dwarf planet in the Kuiper Belt, Haumea rotates incredibly quickly.

* Ceres: Located in the asteroid belt between Mars and Jupiter, Ceres is the largest object in the asteroid belt.

These are just a few of the many dwarf planets that exist in our solar system.