From the Super Mario Wiki
World 2 is the second world explored in Super Mario 3D Land. This world is a yellow field with many blocks, hills and a mountain can be seen in the background. It has five levels, a Mystery Box, and a Toad House. The boss of this world is Boom Boom.
The 4 possible contents of this world's Mystery Box are:
- Having trouble playing?
- The secret area with the coins in the shape of "3D" may be a reference to a secret area in Super Mario Bros. 3 where the coins are in the shape of the number 3.
- When Mario completes World 2-3, the original winning tune from Super Mario Bros. is played. This also plays at the end of Special 1-3.
- World 5-2 was, during early builds, 2-5 as a reference to The Legend of Zelda series.