Generated Structures

Generated Structures are structures or land formations that naturally spawn in Minecraft.

Mineral Veins

 * Mineral Veins are generated structures that contain Ores. They spawn underground and may appear anywhere where there is stone.

Dungeons

 * Dungeons are underground structures that consist of Mossy Cobblestone, Cobblestone, and a Monster Spawner which can spawn Zombies, Skeletons, or Spiders. They contain rare and valuable loot.

Villages

 * Villages are above-ground structures with houses, farms, etc. They almost always contain Villagers and rarely, Iron Golems. Villages often have blacksmiths that contain a single chest filled with useful items. They spawn in Deserts, Savannahs, Snow Plains, or Plains.
 * Farmers in the village can harvest and plant crops.

Desert Wells

 * Desert Wells are naturally generated structures found in Deserts and mesas. They carry an infinite source of water which may be helpful due to Deserts usually containing no water sources.

Strongholds

 * Strongholds are underground structures. They are large, having many wings, rooms and halls. They contain the "portal room", the room in which an End Portal is located. There is a Silverfish spawner in there too. They also contain a few chests. They are rarely found under village wells. They also have a massive Library that contains a hidden chest.

Lava Pools

 * Lava pools are small pools of Lava that spawn randomly in the world. They are less likely to generate than regular water pools. They are more commonly found in Deserts.
 * Lava pools can set fire to any flamible block nearby.

Moss Stone Boulders

 * Moss Stone boulders are generated structures that spawn in Mega Taiga Biomes. They are very rare to find.

Ice Spikes

 * Ice Spikes are generated structures made completely out of Packed Ice. They only spawn in the Ice Spikes Biome, which are very rare.

Abandoned Mineshafts

 * Abandoned Mineshafts are large mineshafts, with randomly generated Rails. They are often connected with Caves. They contain Cave Spider spawners. They do not contain chests. They can also spawn in Mesa Biomes as Mesa Mineshafts.

Caves

 * Caves are openings in the surface that lead underground. They often contain Dungeons, Abandoned Mineshafts, and rarely Strongholds. They also contain ores, lava, and water. They can only be found in infinite worlds.

Ravines

 * They are large cracks in Overworld that often lead to various underground structures and rare ores.

Libraries

 * Libraries are structures with mainly bookshelves present in them. They can only be found in strongholds and villages.

Desert Temples

 * Desert Temples are temples that are found on deserts and mesas, commonly burried with sand. It has a colored hardened clay with the the loot, as well as a trap, below it.
 * The trap contains TNT. The trap is activated when the player steps onto the stone pressure plate.

Glowstone Cluster

 * A naturally spawned structure that is composed of Glowstone. It is found in the ceiling of the Nether Dimension. They are the only way to obtain Glowstone in Survival.

Nether Fortress

 * Colossal fortresses mostly comprised of Nether Brick. They contain chests with valuable loot. Blazes and Wither Skeletons can spawn in here. They are also the only sources of Nether Wart.

Trivia

 * Before Update 0.11.0, Abandoned Mineshafts contained Spider Spawners, and not Cave Spider Spawners.
 * Before Update 0.9.0, there were no generated structures (except Mineral Veins).
 * Caves, in extreme cases may count as an exception, as they can sometimes generate in pre-0.9.0 seeds such as nyan.
 * Ravines were planned for 0.9.0, but were not implemented.
 * However, Ravines may be added in Update 0.14.0.