Java Edition 1.18 Experimental Snapshot 1

1.18 Experimental Snapshot 1 is the first experimental snapshot for Java Edition 1.18, released on July 13, 2021, which introduces new terrain generation and enables features from the preview data pack.

World generation

 * Caves


 * Completely overhauled.
 * Now stretch down to Y=-59.
 * The cavern now generates in 2 layers of different stone bases depending on the depth.
 * Cavern layer above Y = 0 is made up of regular stone.
 * Stone transitions to deepslate from Y=0 to Y=-7.
 * Deepslate now completely replaces stone from Y=-8 to bedrock.
 * Certain types of ores and structures still generate in the deepslate layer, as well as tuff.
 * Dirt, diorite, granite and andesite do not generate in this layer.
 * Dripstone Caves and Lush Caves now generate naturally underground.
 * Contain aquifers, bodies of water with different heights, independent of sea level (Y=63).
 * Aquifers below Y=0 sometimes generate with lava instead of water.
 * Improved old caves to blend in with the new generations of caves better.
 * New carver called crack carver, which appears as a fissure on the ground, like ravines but narrower and can go very deep.
 * New noise caves, coming in 3 forms, cheese, spaghetti and noodle.
 * The original caves still exist with their generation slightly tweaked to better blend in with noise caves.
 * Cheese caves have large stone towers stretching from the bottom of the cave to the top.
 * Very large, often large enough to fly with an elytra.
 * Abundant with aquifers and ores.
 * Spaghetti caves are long, thin caves that have small aquifers and are more similar to original caves.
 * Noodle caves are thinner, squigglier and more claustrophobic variants of spaghetti caves.


 * Mountains


 * Come in 5 sub-biomes:
 * Mountain Meadow
 * The lowest layer of a mountain.
 * Contain flowers and sweet berry bushes.
 * Mountain Grove
 * The second lowest layer of a mountain.
 * Covered in snow, snow blocks and powder snow, and is filled with spruce trees.
 * Rabbits spawn in this biome.
 * Snowy Slopes
 * The second highest layer of a mountain.
 * Covered in snow, snow blocks, powder snow and ice.
 * Goats spawn only in the Snowy Slopes biome.
 * Lofty Peaks
 * The highest layer of a mountain, and will only generate if the mountain is high enough.
 * Generates if the surrounding biomes are too warm for snow capped peaks.
 * Covered in snow and ice.
 * Snow Capped Peaks
 * The highest layer of a mountain, and will only generate if the mountain is high enough.
 * Generates if the surrounding biomes are too cold for lofty peaks.
 * Covered in snow, snow blocks, powder snow, ice and packed ice.


 * Ore veins
 * Large, rare, snake-like ore formations.
 * Copper ore veins mixed with granite generate above Y=0.
 * Iron ore veins mixed with tuff generate below Y=0.

Mobs

 * General
 * Hostile mobs will only spawn in complete darkness.
 * Axolotls
 * Now only spawn in lush caves.
 * Goats
 * Now only spawn in some of the new mountain biomes.

World generation

 * Lush Caves and Dripstone Caves
 * Now generate naturally underground and inside mountains.
 * Deep Warm Ocean
 * Now generates naturally.


 * Ore distribution
 * New ore distribution has been implemented, see the chart.
 * Changed the maximum height of small iron ore blobs from 64 to 72.
 * Reduced copper spawning a bit, to compensate for large ore veins.
 * Slightly reduced the amount of normal-sized iron blobs, to compensate for large ore veins and the increased range of smaller blobs.


 * General
 * Natural variation in terrain shape and elevation, independently from biomes.
 * For example, forests and deserts could form up on a hill without needing a special biome just for that.

General

 * Height limit
 * Has been increased to 384 blocks, expanding 64 blocks up and 64 blocks down, with 320 being the limit upward and -64 being the limit downward.


 * World types
 * Removed the Large Biomes and Amplified world types.

Trivia

 * A  for a version called   was mistakenly uploaded instead of this snapshot at first.
 * Combat Test 6 was actually based upon Java Edition 1.16.2 Pre-release 3.
 * This is the first time that the light level requirements for common hostile mob spawning get changed for a really long time, as the "light level 7 and below" requirement has persisted since the game's early stages.
 * This is the first development version using the term "Experimental Snapshot", which starts the update development before the initial snapshots will begin, sometime in September.

Video
Video made by slicedlime: