Rock-Candy Mines

Rock-Candy Mines is the mountainous sixth world of New Super Mario Bros. U, New Super Luigi U, and New Super Mario Bros. U Deluxe. It is physically the smallest world, and it lies east of Acorn Plains, Sparkling Waters, and Soda Jungle, southeast of Layer-Cake Desert, Frosted Glacier, and Meringue Clouds, and south of Peach's Castle. Rock-Candy Mines is a world filled with tall, pillar-like mountains in somewhat irregular shapes. The name is derived from rock candy. There are also several train tracks acting as bridges in the world. There are ten levels in this world, with seven normal levels, two Towers, and the Castle level; there are no Enemy Courses. The boss of this world is Roy Koopa.

Uniquely, the world map contains several sets of red and blue Stretch Blocks. These blocks correspond with red and blue switches on the map. Pressing a switch of one color causes the Stretch Blocks of the same color to extend and the Stretch Blocks of the other color to retract. Mario and Luigi can only cross gaps with an extended set of Stretch Blocks spanning the gap, so to reach certain levels, Toad Houses, and a Bubble Baby Yoshi, the player must first find and press a switch of the appropriate color. Gaining access to the switches is done by completing certain levels.

There are multiple ways to enter this world. One is to complete Soda Jungle's castle, Iggy's Volcanic Castle (Iggy's Swinging-Chains Castle in New Super Luigi U), normally. The other two are to complete Skyward Stalk or Fliprus Lake, the secret levels of Sparkling Waters and Frosted Glacier, respectively (these are Beanstalk Jungle and Fliprus Floes, respectively, in New Super Luigi U).

Challenge Mode original courses

 * Balancing Act - Special (Original Course)
 * Dark Dark Coaster - Coin Collection
 * Mini Mountaineer - Time Attack (Original Course)
 * Screwtop It Up - Time Attack
 * Swing Into Action - Time Attack
 * The High Road - Boost Mode Challenges
 * Fuzzy Cliff Climb - Boost Mode Challenges (Original Course)

Boost Rush courses

 * Fuzzy Clifftop – Yoshi Pack

New enemies

 * Fuzzies
 * Frost Piranhas
 * Porcupuffers
 * Mega Grrrols
 * Bony Beetles
 * Chain Chomps
 * Bob-ombs
 * Fire Bars
 * Sumo Bros.
 * Missile Bills
 * Boss: Sumo Bro
 * Boss: Roy Koopa

Mario Golf: World Tour
Rock-Candy Mines appears in the Star Pack DLC of Mario Golf: World Tour. It is a remake of Boo Valley from Mario Golf, updated with the style and assets of Rock-Candy Mines.

Super Smash Bros. series
Rock-Candy Mines is one of the sections of the Mushroom Kingdom U stage in Super Smash Bros. for Wii U and Super Smash Bros. Ultimate. The layout consists of a giant Wobble Rock, but occasionally water geysers will shoot up from the bottom of the stage. Some geysers will carry Big Urchins on top of them. Stretch Blocks and giant icicles may also appear.

Monopoly Gamer
Rock-Candy Mines is the eleventh property on the game board in Monopoly Gamer. It is one of two properties in the Yellow Color Set (along with Waddlewing's Nest).

WarioWare: Get It Together!
In WarioWare: Get It Together!, Rock-Candy Mines appears as the setting of the Level 1 difficulty in the New Super Mario Bros. U microgame.

The Super Mario Bros. Movie
In The Super Mario Bros. Movie, Rock-Candy Mines, known as the High Cliffs, appears as one of the locations visited by Mario, Princess Peach, and Toad during their journey to the Jungle Kingdom. They are seen climbing on one of the peaks before admiring the vista on top.

Trivia

 * This is the only world in New Super Mario Bros. U to have two towers, and it is the sixth world in the game. Similarly, the mountain-themed World 6 in New Super Mario Bros. is one of only two worlds in that game that has two towers, the other being the final world.
 * Boss Sumo Bro does not appear on top of the tower on the world map before it is entered it. He appears briefly after his defeat, however.