Grass Land

Grass Land (alternatively Grasslands or The Grassland ) is the first world of Super Mario Bros. 3. It has six regular levels, one Hammer Brother to encounter, one fortress, a Spade Panel, two Toad Houses, and a castle that has been taken over by an airship. In the third level, and in the fortress, Mario can get two out of the three Whistles in the game. Larry Koopa, one of the seven Koopalings, guards this area and is the boss of Grass Land.

The king of Grass Land wears a turban, and has a beard. During the events of the game, he is turned into a dog by the Koopalings; the SNES and Game Boy Advance versions of Super Mario Bros. 3 instead see him turned into a Cobrat.

The world map included in Super Mario Advance 4: Super Mario Bros. 3 shows that Grass Land is bordered by Desert Land to the south and Pipe Land to the east. Likewise, the opening implies that Grass Land is in close proximity to the Mushroom Kingdom.

The Adventures of Super Mario Bros. 3
In The Adventures of Super Mario Bros. 3, Grass Land does not make an explicit appearance; however, its map shows up as the opening curtain when the Mushroom Kingdom is the episode's main setting, implying them to be one and the same or at least its animated equivalent. The Mushroom Kingdom (also sometimes called Mushroomland) appears in almost every episode at some point, as it was where Mario and his friends live. Mario and Luigi live in Toad's house, while Princess Toadstool lives in the Mushroom Castle.

Trivia

 * A rendition of the theme for Grass Land is played on the Level Up Option Screen in the game Paper Mario. The same applies to the Rec Room in Super Mario 64 DS and the 100 Mario Challenge and Course World in Super Mario Maker.
 * Another rendition of the theme is used for Munchlax's Berry Bonanza game, on the Pokémon website.
 * A medley of this theme and the Super Mario Bros. overworld theme is used for the theme of Mario's Pad in Super Mario RPG: Legend of the Seven Stars and Mario & Luigi: Superstar Saga.
 * Another medley of this music, mixed with the overworld theme, can be heard on the stage Yoshi's Island in Super Smash Bros. Melee, Super Smash Bros. Brawl, and Super Smash Bros. for Wii U, and on any Mario stage in Super Smash Bros. Ultimate.
 * Another medley of this music, which is mixed with the map music for World 1 from New Super Mario Bros. Wii can be heard on the map of World 1 in Puzzle & Dragons: Super Mario Bros. Edition.
 * Despite being called Grass Land, most of the terrain on the world map appears to be sand. It could, however, be dried grass, which is tan in color.
 * Grass Land is the only world to keep its name intact in all versions of Super Mario Bros. 3 (including Super Mario All-Stars and Super Mario Advance 4).