Traditionally our schools have taught that Pluto was one of the planets of our solar system. Of course recently Pluto was reclassified and is no longer called a planet but a minor planet.
We can see that Pluto is not the largest and many others are nearly as big.
In addition it is likely that even larger bodies (minor planets) will be found further out as we now know there are great numbers of objects out there in the darkness beyond Pluto.
Thanks to The Planetary Society for the picture.
I hope primary school teachers will take note of this!