Superflat



Superflat (sometimes called Flatlands) is a World Type, first introduced to Minecraft in Snapshot 12w01a, replacing the normal varied terrain of The Overworld with a thin flat layer of dirt.

The terrain consists of one layer of Bedrock, two layers of Dirt, and one layer of Grass; the surface of the world is completely flat and at height y = 4, with the exception of villages. Since the height limit (256) is unchanged, there is then slightly less than twice as much vertical height available to build above-ground structures as compared to a normal world. Mobs spawn as normal, including slimes; however, due to the entire map being open to the sky, there is no “Void Fog” as would ordinarily be caused by being close to the bottom. If the sky was blocked out for a long distance, there would be void fog in survival, but not creative.

Because of there being chests in villages, and villages frequently spawning near the spawn point, it's possible to use superflat as a challenge map. However, the high amount of slimes makes this extremely difficult.

The Nether and The End generate normally; they are not flat. In order to create a Superflat world in SMP, the level-type flag in server.properties must be "FLAT", instead of "DEFAULT".

The superflat world type seems to be based on the 'flat' map type in indev.

Future
Jeb is considering adding a Spawn Chest to this World Type if the player wishes to use it for Survival sometime after Minecraft 1.1. Although it never did get approved but it probably will in the future.

Resources that can be found in Superflat world
The resources below can always be found, regardless of the "Generate structures" option.

The resources below can only be found if the "Generate structures" option is enabled.

Village chests may contain those items:

Most mob drops can also be found by killing them.

Bugs

 * If the player breaks the Bedrock barrier, the player can see that the Void has the same color of the sky while the player is above y=0, but looks normal (black) when the player is below y=0.
 * There is no consistent spawn point unless the player has slept in a bed; the player may respawn far from the previous spawning location without anything in sight. This may be due to the lack of ground at the usual height of about 64.
 * Slimes are extremely common since the level of the land is so low. Also, no other hostile mobs can spawn during the day because there are no caves, so slimes spawn much more often
 * If you play in a super flat world generated in 1.1 in snapshot 12w06a, the snapshot may change the biome to snow and will cause any un-generated chunks to form as a normal world, this can also happen if you play a superflat world in Minecraft 1.0.0. In addition, this will cause the void particles to appear aboveground.
 * If you overwrite a superflat world with a default world of the same name, some chunks (and sometimes massive areas) may remain superflat, though the grass color will change with the biome.

Trivia

 * Although extremely flat and barren, a player can survive and even flourish in a superflat, as long as Generate Structures is on. The player has access to mob drops, as well as wheat found in NPC Villages. Also, if the player finds any saplings in a blacksmith chest they can start a tree farm, giving them unlimited wood.
 * With Generate Structures on, the player also has access to the materials that the NPC villages are constructed. Blacksmith chests sometimes have saplings, which would allow the player to grow trees otherwise unavailable. Wood found in villages or grown from saplings can be used as fuel, or smelted into charcoal. There can also be found lava at a blacksmith's, and water used on the farms, to make an infinite supply of stone. However, unless they find iron or a bucket in a chest or kill an Iron Golem, this is nearly impossible. It is also possible to find obsidian in a blacksmiths chest in an NPC village.
 * The Nether is unaffected by the Superflat world type, generating normally if visited from a Superflat Overworld, although the players' portal in the nether would spawn very close to the bottom bedrock. Visiting the Nether is normally extremely hard, as you would need to get a bucket (possibly from a village chest) and take water from a well and pour it on the lava in multiple blacksmiths (Obsidian blocks can also be found in the blacksmiths chests). Then, you would need to mine it with a diamond pickaxe made from blacksmith chest diamonds and light it with a Flint and Steel made from Flint from the paths and Iron Ingots from blacksmith chests. It is also possible, though extremely rare, for Lightning to light a portal. Alternatively, you could create a portal using a mold made of dirt and lava, placing water on the lava after each step. However, you would have to visit five different forges (which have two lava source blocks each) to obtain the amount of lava necessary for this.
 * While Strongholds can not generate on these worlds, a player may visit The End in SMP by spawning an Ender Dragon, killing the spawned Ender Dragon and travelling through the End Portal created upon its death. Like the Nether, the End is unaffected by the Superflat world type.
 * NPC Villages seem to spawn more frequently on superflat worlds than normal worlds, possibly due to the fact that villages spawn more often on flat areas, such as a desert or plains.
 * When pressing F3, the biome corresponds to where a biome would be, although the terrain is the flat.