Hm, hm, hm! A dungeon is beneath a castle, that's true, but a dungeon is all about how it feels! If it's dangerous and full of monsters, then it's a dungeon, see?

[Like beneath the old schoolhouse that was filled with ghosts, or the towers!]

It's just gotta be an old and dangerous place! I walk through them all the time for work, buuuut there are people with me so the monsters don't eat me! Usually.