Minecraft wiki entry for Superflat, associated text: Superflat worlds also allow the player to access The End, which generates a normal dimension of floating islands, if strongholds are enabled, by spawning in an End Portal (block) using commands or by building your own End portal. In Java Edition 1.16-1.18.1 strongholds do not generate naturally in a default superflat world but in Java Edition 1.15.2 and prior or Java Edition1.18.2 and above they can, requiring either a world in 1.15.2 to be updated to 1.16 after world creation or a custom superflat preset to generate strongholds naturally for Java Edition 1.16-1.18.1 versions.