The Nether

The Nether is a dangerous underworld-like dimension filled with fire, lava, fungus-based vegetation, and many hostile mobs.

Accessing


To access the Nether, the player must construct a nether portal in the Overworld (portals created in The End do not activate). To create the portal, the player must first build a rectangular obsidian frame, ranging in size from a minimum of 4×5 to a maximum of 23×23. Once the frame is built, it can then be activated by placing fire within the frame, using flint and steel, fire charge, dispensers or any materials.

An activated portal allows most entities (with the exception of the wither, the ender dragon, and entities riding or being ridden by another entity) to be transported to a corresponding portal in the Nether. In Survival, the player must stand in a nether portal for 4 seconds to get to the Nether. The player can step out of a portal before it completes its animation to abort the teleport. The portal generates a sound effect while the player is inside it. If there is no corresponding portal, a new 4×5 portal is created. The portal can be destroyed by breaking the obsidian frame, by a nearby explosion, or by placing water in the Overworld or lava into it with a bucket or dispenser. Any of the blocks in the corners can be destroyed without destroying the portal.

In the Old world type, it is impossible to construct a nether portal. The portal block must be placed using cheats. When done, the Nether has the same 256×256 borders as the Overworld, and if a nether portal is then made in the Nether, it can spawn the player outside the world barrier.

Traits
Bedrock comprises the top (below layer 127) and bottom 4 layers in a rough pattern, essentially making the Nether 127 blocks high unlike the Overworld's 256. In the infinite worlds of the Java and Bedrock Editions, the Nether is also horizontally infinite. $$, the build limit in the Nether is 128 blocks, despite it being 256 in all other dimensions.

The Nether has no daylight cycle and no weather. Natural sources of light include fire, lava, portals, shroomlights and glowstone. Even with a light level of 0, the Nether has a dim ambient light (roughly equivalent to light level 8 in the Overworld). Light otherwise functions exactly the same as it does in the Overworld and the End.

All the flora in the Nether is fungus-based as opposed to plants. The Nether "grass" consists of specialized Nether mycelium (known as "Nylium"). The Nether features its own unique fungi (including Nether wart), as well as equivalent huge fungi which serve as trees. The stems of the huge fungi function as logs. Other fungus-based vegetation is present in the Nether, including vines and roots.

Most creatures found in the Nether are hostile and potentially dangerous.

Locations in the Nether correlate to Overworld coordinates, but horizontal Overworld distances are scaled down by a ratio of 8:1 for travel in the Nether. Therefore, traveling one block in the Nether means traveling eight blocks in the Overworld. For example, in a perfect scenario, a player who enters a portal in the Overworld at x=0, z=0 and travels in the Nether to x=1000, z=1000 returns to the Overworld at x=8000, z=8000. This makes portals a useful tool for traveling long distances in the Overworld.



Most items and blocks in the Nether function the same as they do in the Overworld, with a few notable exceptions:


 * Beds explode and cause fires when a player attempts to sleep in one. It has an explosion power of 5. The explosion is larger than that of TNT, which has an explosion power of 4. They cannot be used as a respawn point.
 * One has to use a powered respawn anchor to respawn in the Nether, but when it runs out of charges, the player once again respawns in the Overworld.
 * There is no way to place liquid water in the Nether without the use of commands, except inside a cauldron. These can be used to put out a player on fire, but are difficult to center oneself in.
 * Using water buckets produces steam particles and a hissing sound, leaving the player with an empty bucket.
 * Ice that is melted or smashed in the Nether does not produce water.
 * A wet sponge instantly becomes a regular sponge when placed.
 * If somehow placed using cheats or when placed inside a cauldron, water takes on a reddish-brown color.
 * Lava flows twice as far (eight blocks) and six times as fast in the Nether compared to Overworld, basically water's equivalent flow characteristics from the Overworld.
 * Grass blocks and leaves take a dead-looking brownish color since the Nether is a warm biome.
 * Maps generate a brown-gray static pattern. The player's direction indicator spins randomly; its location is still relative to the player's location in the Nether, except in the New Nintendo 3DS Edition, where it is always in the center of the map. Usable significantly for lava ocean travel via strider. An offhand-equipped shield minimizes the map to help see one's strider footing.
 * Clocks spin wildly, making it impossible to tell the time while in the Nether. Compasses also spin wildly unless connected to a Lodestone, which they then point toward.
 * Snow golems rapidly take fire damage and die, due to the Nether being a warm biome. However, they can survive if they have the status effect.

Environment
The Nether features unique cave-like terrain with no sky. Lava and fire are common hazards everywhere in the Nether. Areas distant from the player are shrouded in a fog.

Biomes
The Nether is divided into several biomes just like the Overworld, each featuring unique terrain, mobs, structures, ambience, etc. There are currently five biomes in the Nether.

Generated structures
The Nether contains a variety of unique generated structures. Though equally vast, it contains far fewer types of generated structures than the Overworld.

Terrain features
The Nether has a lot of different terrain features which generate within the biomes of the Nether.

Mobs
The Nether is home to its own share of mobs, most of which are fire- and lava-proof. Skeletons, chickens, and endermen are the only Overworld mobs that can naturally spawn in the Nether; $$, baby zombified piglins may spawn as chicken jockeys.

Other Overworld mobs do not naturally spawn in the Nether but can be teleported through portals (with the exception of withers and ender dragons).

Naturally generated
Naturally generated blocks includes those that are created through the world seed.

Naturally created
Naturally created blocks are created through a combination of events that lead these blocks to be placed by natural causes, not by the player.

Structures
These blocks are generated as part of nether fortresses, bastion remnants, and ruined portals, but only when the "generated structures" option is on.

Generation in Bedrock Edition
$$, when Overworld biomes are generated in the Nether dimension, at layer 31, the lava sea is replaced with water sea. Passive mobs cannot spawn, while monsters can. Overworld structures cannot generate, but nether fortresses still generate. Nether mobs such as zombified piglins and magma cubes can spawn only as part of the fortress. Overworld mineral veins still generate as normal, but no Nether vein mineral generates. Despite lava springs being the only light source, the lighting is reasonable, as players can still see without light sources. The fog is the same as sky color in the Overworld. No trees generate, and only some vegetation such as kelp, seagrass, flowers, grass, fern, sugar cane, cactus, and mushroom can generate in sparse quantities, and disks are also rare. Additionally, the Nether music track is exclusive to this dimension.

Folder
$$, the Nether is stored in. Deleting this file resets the Nether, so that all player-made changes and buildings in that dimension are undone.

$$, the  folder contains several collections of chunks. Some of these files are used for the Nether, but it is impossible to tell which ones simply by reading the file name.

Advancements
There is a whole tab dedicated to the Nether in the advancement system, all involving visiting the Nether in some way in order to advance.

Trivia

 * Upon entering the Nether as a single player, the passage of time freezes in the Overworld, resuming when the player returns unless the command is used. This is due to the spawn chunks no longer being ticked, and not chunks loading and unloading as some players believe. The spawn chunks are kept loaded when there are no players in the Overworld, but most stuff other than basic redstone stops working.
 * The numbers for the 3 dimensions are -1=The Nether, 0=The Overworld, 1=The End. This implies that the Nether is the next dimension over from the Overworld in the "down" direction and The End is the next dimension over in the "up" direction. Although it is confirmed that the 3 dimensions are not supposed to be stacked vertically.
 * $$, if a section of the bedrock ceiling is removed (e.g., through commands) mobs can spawn directly below where the ceiling should be, despite the surface density cap in the Nether being 0. This implies that the Nether is always considered a cave.
 * Nether's soundtrack feature loud roars, and sometimes a blurred version of ghast's ambient can be heard.
 * $$, the world size is limited, making the Overworld-Nether ratio 1:3 (1:6 in Switch Edition) compared to the 1:8 in Java Edition.
 * The edge of the nether is surrounded by bedrock walls.