They just added New Dimensions to Minecraft (1.16 Snapshot Update 20w21a)

Here's a look at the NEW custom dimensions added to Minecraft 1.16. You can now add your own custom worlds and dimensions! This is awesome!PLAY Block Ness Mo

Java Edition 23w13a_or_b – Minecraft Wiki

Minecraft 1.16.2 Snapshot 20w28a (Custom Everything)

Minecraft 1.16 Update Mod (snapshot 20w18a Update!) - Modding

Iiiiiiiio

Java Edition 20w14∞ – Minecraft Wiki

Java Edition 1.17 – Minecraft Wiki

Java Edition 21w20a – Minecraft Wiki

Java Edition 1.18 Experimental Snapshot 1 – Minecraft Wiki

Java Edition 20w14∞ – Minecraft Wiki

Java Edition 1.9 – Minecraft Wiki

Nether Update – Minecraft Wiki

Java Edition 22w18a – Minecraft Wiki