God, Mercury is the worst in everyway. Closest to the sun, ugliest and it's not even too impressive in size.
What a bitch it is. Now Pluto, that was a planet!
Pluto and Charon could actually be considered a double dwarf planet system. They're close enough in size that their center of mass isn't actually on Pluto.
Charon doesn't orbit Pluto, they orbit each other.