World 1 (New Super Mario Bros.)

World 1 is the first world encountered in New Super Mario Bros. for the DS. Bowser Jr., who is the boss of every tower, appears here, while Bowser is the boss of the first castle.

World 1 has 5 normal levels, a tower level, a castle level, and a bonus water level (World 1-A) that can be bought for five Star Coins.