Stronghold

Strongholds are Generated Structures added in Update 0.9.0. They are the rarest generated structures in Minecraft Pocket Edition.

Locating
Unlike most structures, Strongholds are intended to be difficult to locate through conventional means, providing almost no outward indication to exposed areas unless exposed through the surface or through Water. They are usually only encountered by chance, and rarely generate beneath Village wells. However, they will be locatable using Eyes of Ender once they are added to the game.

Layout

 * Strongholds vary in size but are generally large and complex like a maze, containing multiple rooms, corridors, Libraries, stairwells, Doors, and other features.
 * They mainly consist of Stone Bricks, Mossy Stone Bricks, and Cracked Stone Bricks.
 * Strongholds are lit by enough Torches to provide visibility in most areas, though not enough to suppress Mob spawns.
 * In the Portal Room there is a Silverfish Spawner.

Loot
It is possible to get loot from Chests present in Strongholds. They are:
 * Diamond_(Gem).png Diamonds
 * Apple icon32.png Apples
 * Ink_Sack.png Ink Sacs
 * 45px-Armor.svg.png Armor
 * Ironitm.png Iron Ingots
 * Emerald.png Emeralds
 * GOLD.png Gold Ingots
 * Bread2.png Bread
 * Paper.png Paper
 * Book.png Books
 * Enchanted Books
 * CoalFinal.png Coal
 * String.png String
 * Gunpowder_item.png Gunpowder
 * Saddle.png Saddles
 * Diamond Horse Armor.png Diamond Horse Armor
 * Gold Horse Armor.png Gold Horse Armor
 * Iron Horse Armor.png Iron Horse Armor

Trivia

 * Very rarely, they will intersect a Mineshaft and/or a Dungeon.
 * Extremely rarely, they will spawn above-ground at the bottom of Deep Ocean Biomes.
 * Strongholds contain an End Portal, but they do not yet function in Pocket Edition.
 * Strongholds are the only structure where Silverfish spawners are found.
 * Eyes of Ender naturally spawn on the End Portal Frame, but they cannot be obtained separately as there are no Ender Pearls.
 * Most of the Blocks in the entire Stronghold are actually Silverfish Stone.
 * Strongholds are by far the biggest generated structures, often being even larger than Villages.
 * The biggest rooms in Strongholds are the Libraries. They contain several hundred Bookshelves, which makes them the ideal place to get Books.
 * The Libraries also contain Chests with Books and Paper inside.
 * Strongholds may generate at Bedrock level, therefore cutting the Bedrock layer and making it possible to access the Void in Survival Mode.
 * There is an Android-exclusive bug where Strongholds cannot spawn.
 * I a player leaves a world where there was supposed to be a Stronghold, it will crash the game.