World 6-4

World 6-4 is the name of several different levels:
*World 6-4 in Super Mario Bros..
*World 6-4 in Super Mario Bros.: The Lost Levels.
*World 6-4 in Super Mario Bros. 3.
*World 6-4 in New Super Mario Bros..
*World 6-4 in New Super Mario Bros. Wii.
*World 6-4 in Super Mario 3D Land.
*World 6-4 in New Super Mario Bros. 2.
*World 6-4 in Puzzle & Dragons: Super Mario Bros. Edition.
*World 6-4 in Super Mario Maker for Nintendo 3DS.