-"When i first laid my eyes on it, i fainted." - Xisenin
The Minecraft Dimension is like Minecraftia, but a whole dimension of it. There are planets, too.
Xisenin discovered it when he invented an interdimensional portal, which took him there. He fainted immediately when he arrived, and was taken in by some Minecraftians. Xisenin was elated, of course, and became their friends. What he discovered was that anyone who travels into it becomes a Minecraftian. He spends a lot of time in this dimension, learning about the history of current planets and stuff.