In Indev, there was a map type called "Floating." It generated floating islands full of terrain based on the World Theme.
The Sky Dimension was first announced when Notch tweeted a picture of the dimension. It was probably made to be like a "heaven," because the Nether was considered to be like a hell. The Sky Dimension was not completely confirmed until Notch released an update via Twitter stating: "And because PC Gamer made such a big deal of the Sky Dimension, I guess I'll have to finish it. Consider it confirmed."
In a live webcast on the Swedish gaming site feber.se Notch revealed that the Sky Dimension would "probably be a dream world" and that when "you go to bed there is a certain chance that you get teleported into the dream world instead. Then you will be able to do it on purpose later on."
The original concept of the Sky Dimension was later rebranded as "The End," a dark place fittingly referred to as the "end of the game," home to the endermen and the ender dragon, and a total conversion of the original idea.
Notch tweeted much later that a different "Skylands" dimension probably was still in the making. This version, completely separate from the End, was set to replace the original idea. However, Jeb later stated that returning the Sky Dimension was not planned and therefore is unlikely to be done.
In this version of the Sky Dimension, the buildup of the world blocks-wise is very much like the Overworld, but it is always midday and it does not rain or snow (though cloud cover does appear as if it were raining). Although uncommon, it is possible to find sugar cane, redstone, lapis lazuli, and more rarely diamond. Like the normal world, you can also find dungeons, Iron, coal, and gold. The only mobs that spawn in the sky dimension are chickens; no other mobs (including hostile ones and squid) spawn. Below the islands of the Sky Dimension is nothing but the Void and a layer of clouds.
Later, the Sky Dimension was hidden within the region 0 (Overworld) code. However, starting in Beta 1.9-pre3, it was given its own region: Region 2, with Region 1 being the Nether. However, instead of Sky Dimension chunks generating within its region, they would generate in the Overworld on Multiplayer servers. This is most likely due to an issue with map generation and saving causing Sky Dimension chunks to save over Overworld chunks rather than being made in their own, separate map files like the Nether does. If a world with Sky Dimension chunks is brought from multiplayer to singleplayer, the area of the chunks will always be plains biome, even if snow generated naturally on the ground.
The first released screenshots of the Sky Dimension:
- Gallery on imgur