Ice Land

Ice Land (alternatively Iced Land, Winter Wonderland , the Ice World , or Ice Country ) is the sixth world in Super Mario Bros. 3. It is the largest world in the game, with ten levels, three Hammer Brothers, three Fortresses, three Spade Panels, two Toad's Houses, and a king's palace. As the name implies, it is a frozen wasteland covered with slippery floors and frozen lakes. Lemmy Koopa takes over this icy kingdom by stealing the royal magic wand and turning the king into a seal (a Monty Mole in the game's remakes). The map in Super Mario Advance 4: Super Mario Bros. 3 shows that Ice Land is north of Dark Land, and east of Pipe Land.

The Adventures of Super Mario Bros. 3
In The Adventures of Super Mario Bros. 3, an unnamed kingdom (presumed to be Ice Land given the obvious similarity) only appeared in the episode "Life's Ruff", where it had a different ruler named King Windbag. He bullied his servants and never said "please", but when Hip and Hop came, they stole his wand and turned him and Luigi into dogs and harassed them for a bit, but were eventually defeated and returned to Dark Land.

Super Mario World television series
"Ice Land" appeared in the first episode of the Super Mario World television series, "Fire Sale", where it appears to be depicted as an icy cavern in close proximity of Dinosaur World. Here, it is under the control of Kootie Pie, who had stolen Mama Fireplant to make it warmer. Unfortunately, Ice Land started to melt because of the heat, but the Mario Bros., Princess Toadstool, and Yoshi soon saved Mama Fireplant and Ice Land.

Trivia

 * The overworld theme from this world plays whenever Jolene (going by the name of X) e-mails Mario in Paper Mario: The Thousand-Year Door.
 * It also appears in Mario Party during the Pedal Power and Ghost Guess mini-games.
 * In World 6-4, a made of Brick Blocks appears in the sky. To reach the cross, Mario or Luigi must fly up there in Raccoon form.
 * This is the only world of the game that is possible to go backwards from using a Magic Whistle, as using it in the sixth world will allow one to return to the fifth. However, in worlds 5 and 8, using it can cause one to return to the current world.