World 3 (New Super Mario Bros.)
From the Super Mario Wiki, the Mario encyclopedia
World 3 is third main world in the game New Super Mario Bros.. This world features a large beach-covered island, with many ocean- and beach-themed levels featuring Cheep-Cheeps, as well as the first Ghost House in the game. World 3 has a total of eleven exits, and the boss of the world is Cheepskipper. After the completion of this world, the player instantly gains access to World 5.