The Sun is 400 times wider than the Moon and 400 times farther away. That coincidence is the only reason total solar eclipses exist.

The two discs appear almost exactly the same size from Earth, so the Moon can cover the Sun's face and leave the corona showing. No other planet in the solar system gets a fit that neat, and it's temporary: the Moon is receding, and in a few hundred million years it will be too small to cover the Sun completely.