Dungeon

For actual dungeon, see prison.

See also: labyrinth, dungeon crawler

The labyrinthine bit is very important, as even places used for meaningful things becomes dungeons when their design becomes a nonsensical labyrinth. Commonly dungeons are either underground or tall towers, windows if they exist either do not offer escape from the dungeon and there's usually no good shortcuts back to safety outside.

Most egregious examples of dungeons is when the location is completely unidentified as anything specific (not a cave, not a stronghold, not anything).