[Alas Babylon!]

Side by side, relative size:

Charon's a monster of a big moon compared to Pluto!

[Moonman62]

Charon’s a monster of a big moon compared to Pluto!

...

The Earth’s moon is also considered large compared to the Earth and very close as is Charon to Pluto. Some have said the Earth and Moon should be called a binary planet.

Both systems were probably created by impact events.