Dungeon

Dungeons are naturally generated underground structures that were added in Update 0.9.0. Dungeons are small rooms with a monster spawner and some chests that contain valuables and rare items.

Spawners
The mob spawners in a dungeon can spawn a zombie, skeleton, or spider. The monster spawners can be disabled by providing adequate lighting or destroying the spawner itself.

Loot
It is possible to find the following loot in a dungeon:

Spawners
Four types of spawners may be found.

Trivia

 * Dungeons are very hard to locate, though they can be located by listening for mob sounds underground. Note that it must distinctly come from one mob. Also it could just be an indicator of an unlit and dark area nearby. However, dungeons are the easiest of the three underground structures to find.
 * Sometimes, dungeons may not contain chests at all.
 * Before 0.9.4 Alpha, there was a bug that caused the monster spawner to spawn hostile mobs, even when on peaceful.
 * Dungeon chests may contain Saddles. This isn't a glitch, but the saddles still do not function until a future update. Saddles can be also found in villages. It is also possible to catch Saddles by Fishing.
 * Rare items inside dungeons are usually Saddles, armor, and valuable ores.
 * Very rarely, one dungeon may intersect the other, forming a double dungeon. Even more rarely, three dungeons will intersect. The chance of such is lower than 5%.
 * One way to locate a dungeon in a cave is to observe the quantity of mobs that spawn in that cave. If The Player thinks that the mobs are way too many to have spawned naturally, then there is a dungeon nearby.
 * Some dungeons have one chest.
 * Dungeons can be inside abandoned mineshafts.
 * This is one of the three ways to obtain mossy cobblestone.
 * This is the smallest generated structure ever in minecraft.
 * The can spawn under sea level.
 * Some dungeons may not have a mob in its spawner, have no spawner at all, or have invisible chests that contain nothing.
 * In the PC version, nametags, music discs, and horse armor can be found in dungeon chests.
 * This may be added when these items are.