World 7 (Super Mario Bros. 2)

World 7 (known as Chapter 7 in Yume Kōjō: Doki Doki Panic) is the seventh and final world in Super Mario Bros. 2. Taking place high above the clouds and in the sky, this is where Wart resides.

This world has only two levels instead of three, the least of any world in the mainline Super Mario series. In the original story of Yume Kōjō: Doki Doki Panic, this is explained as the final page being the ending of the book that was torn out, which would have been the missing third level.