Desert Land

Desert Hill (known as Desert Land in the original NES version) is the second world of Super Mario Bros. 3. It contains five levels, two Boomerang Bros., a fortress, three Toad Houses, and special Desert and Pyramid stages. Most of the levels have quicksand or Fire Snakes. The last Warp Whistle can be acquired by defeating the hidden Fire Bros. level (to access the level, is to take a hammer and smash the rock in the far upper-right corner of the screen, which will give access to a hidden part of the map where the Fire Bros. are located).

The Desert Hill is home to some of the rarest enemies in the game, including the Fire Bros., the Angry Sun, and Tweester (an obstacle that is exclusive to the desert level). Morton Koopa Jr. guards this area and is the boss of Desert Hill.

2-1
The first level of Desert Hill takes place in a sandy area with many Brick Blocks and some metallic constructions filled with coins. The level also introduces the Pile Driver Micro-Goomba, a small Goomba that disguises itself as block, and the Fire Snake, a creature that is ablaze and that can only be defeated with a Starman or a swipe from Raccoon Mario's tail. A Warp Pipe surrounded by blocks can be found by Raccoon Mario over the first metallic construct. It will lead into a room with a P-Switch and some Silver Coins.

There is another secret room in this level with another P-Switch, but nothing else.

2-2
This level takes place in an area with many quicksand fields and a pond filled with water and Cheep Cheeps. The player should watch out for the Venus Fire Traps that live in the quicksand, and if Mario falls in such a sandpit, he should hurry and get out soon or he will be engulfed and lose a life. The latter, flooded half of the level is traversed by a floating platform. Mario has to jump over the hovering Brick Blocks, or he will be pushed down into the water filled with enemies. A hidden P-Block can be found in one of the blocks that will turn all the other blocks into coins. If the player manages to collect every coin in the level, a White Toad House with an Anchor inside will appear.

Fortress
The fortress of Desert Hill is a building with two stories and several enemies inside. The stage introduces Thwomps, big stones that will attempt to crush Mario when he walks underneath them, as well as Boos, timid enemies that will only move when Mario's back is turned at them. Dry Bones also inhabit the first floor of the fortress. The player can gather many extra lives from them by repeatedly jumping on them and using Raccoon Mario's ability to slow his descent to hit them again when they regenerate. After a big room with spiked traps, Mario will encounter Boom Boom, the guardian of the fortress.

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This level is set in an area with some small pyramids composed of blocks and platforms. Many enemies like Fire Snakes and Koopa Troopas patrol the areas and there are also some bottomless pits. In the second half of the level, there are block pyramids, guarded by Pile Driver Micro-Goombas that hide between the real blocks and try to launch surprise attacks at Mario. The player has to be careful not to get ambushed. Somewhere over the stage, a P-Switch can be found that turns all Brick Blocks into coins. The level exit is accessed by a Warp Pipe, guarded by two Koopa Troopas.

Desert
The desert is an area filled with quicksand pits, and it is automatically entered once Mario touches the level on the world map. A rare enemy called Angry Sun resides in this level and will follow the player through the whole level. At the beginning, the Angry Sun hovers at the top-left corner of the screen and remains inactive. Once the player passes through the Tweester however (a task that can only be done by jumping while running at full speed), the Angry Sun begins to attack Mario by swooping down, trying to burn him. The player can either avoid the sun's attacks and try to reach the goal, or hit a nearby Koopa Troopa and dispatch the sun with its shell. Unlike most levels in Super Mario Bros. 3, the player has 200 seconds to complete this level, instead of the usual 300.

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A level filled with Goombas, Venus Fire Traps, and Boomerang Bros.. There are two ways to traverse this level. The normal one is to take the bottom path, dealing with all the enemies and eventually reaching the goal. The second one can only be accessed by Raccoon Mario. At the start, the player can take a secret path by gaining enough momentum and flying upwards through a row of Brick Blocks. The secret path is a path filled with coins, and its only enemies are two Paratroopas.

2-5
Another level that takes place in an open desert area. This level introduces the Chain Chomp, a chained, cannonball-like dog on a massive chain that tries to attack Mario within its range. Halfway through the level, a Magic Vine can be found by smashing a Koopa Shell against some Brick Blocks. The vine leads to a Warp Pipe which gives access to a bonus room with a P-Switch. When reaching the level end, the player should watch out for the Chain Chomp that is positioned beneath the goal.

Pyramid
The player begins this level in an open area, but the majority of the level takes place inside a big pyramid. The interiors of the pyramid are composed of an underground maze filled with Buzzy Beetles. The player has to choose the right path to proceed. Occasionally, a wall of Brick Blocks will hinder Mario's progress. These blocks have to be smashed either by a Buzzy Beetle Shell or Raccoon Mario's tail swipe. Along the way, a Warp pipe that is reachable through an invisible block can be found. The pipe will lead the player to a bonus room and serve as a shortcut through the level. The goal is found at the other end of the pyramid.

Airship
In the palace, Mario finds the transformed Mushroom King and a nervous Toad who presents Mario with a quest to stop Morton Koopa Jr.. Shortly after, Mario boards the Airship of the Koopaling. Another level filled with Cannonballs and Bullet Bills has to be traversed. Additionally, an enemy called Rocky Wrench is introduced, a mole-like creature that throws screwdrivers at Mario.

After Mario enters the gray Warp Pipe at the end of the stage, a battle with Morton Koopa Jr. emerges. The Koopaling attacks by jumping and shooting energy blasts from his Magic Wand, just like Larry Koopa did in the previous world. After Morton has taken three hits to the head by Mario, he will be defeated and leave the Magic Wand behind, which transforms the King back to his former self.

Trivia

 * Desert Hills (a course in Mario Kart DS and Mario Kart Wii) is based on this world.
 * It also appears in the Super Mario Bros. film, as the Koopahari Desert.