World 4 (New Super Mario Bros. Wii) - Super Mario Wiki, the Mario encyclopedia

World 4 is the fourth world in New Super Mario Bros. Wii. It features several tropical islands, therefore, most of its levels are water-themed and make rather good use of the Penguin Suit, which can glide over water and allow Mario to swim better. Also, on the map is a

World 8-4 (New Super Mario Bros. Wii) - Super Mario Wiki, the Mario encyclopedia

World 8-1 (New Super Mario Bros. Wii) - Super Mario Wiki, the Mario encyclopedia

World 4-3 - New Super Mario Wii Guide - IGN

World 7 (New Super Mario Bros. Wii) - Super Mario Wiki, the Mario encyclopedia

New Super Mario Bros Wii, The Parody Wiki

World 9 (New Super Mario Bros. Wii) - Super Mario Wiki, the Mario encyclopedia

World 4-2 (New Super Mario Bros. Wii) - Super Mario Wiki, the Mario encyclopedia

World 4-4 - New Super Mario Wii Guide - IGN

New Super Mario Bros. Wii, MarioWiki

Boo - Super Mario Wiki, the Mario encyclopedia

World 4-4 - New Super Mario Wii Guide - IGN

World 4-1 (New Super Mario Bros. Wii), MarioWiki