More big moons in the solar system
The solar system has four rocky planets, one with a large moon. The moons of the four giant planets are small compared to their primaries but Ganymede, Titan, Callisto and Io are all bigger than Luna also Europa and Triton are bigger than Pluto. There are currently five dwarf planets: Pluto and Eris both have relatively large moons. So far three Trans Neptunian Objects also have large moons (Orcus, Salacia and 2007 OR10)
(The JWs try to tell me Earth is really unusual because of its large moon. I like to show them this pretty picture)