Minecraft wiki entry for Defeating_a_dungeon, associated text: Dungeons also generate next to caves. Turning sound on can be significantly helpful and subtitles‌[JE only] still help. If you hear a lot of mobs of the same type in one direction, chances are there's a spawner in a dungeon. The spawner has a chance to be a zombie (50% chance), skeleton (25% chance), or spider (25% chance) spawner. Unlike most generated structures, dungeons cannot be located with /locate.