Rainbow Course

A Rainbow World is a special course in New Super Mario Bros. 2 triggered by finishing a level with the last two digits of the Time Limit being "11". Then, the original Super Mario Bros. "Course Clear" theme will play, along with a firework going off and a rainbow appearing. Then, Mario can then head to the beginning of the world, where a Rainbow World has opened up. At the beginning of every Rainbow World, Mario must enter a Cannon Pipe to be launched to a Coin Heaven-type area with, of course, lots of coins, 10 Gold Coins, and even a single 100 Gold Coin. However, all rainbow worlds are slightly different from each other. If Mario falls off the course, he will not die, but it will close up and Mario has to satisfy these conditions to reopen one.

Trivia

 * The music is a sparkly remix of the New Super Mario Bros. series Coin Heaven theme.
 * Mario falling out of a course without dying is also used with secret courses in Super Mario 64.