Pipe Land

Pipe Land (more commonly known as the Pipe Maze) is the seventh world in Super Mario Bros. 3. Pipe Land consists of nine levels, two Fortresses, three Toad Houses, and two special Piranha Plant levels. The overworld map consists of many islands linked by a confusing network of pipes. The levels in this world often have complex pipe networks with in.

The labyrinth world of Pipe Land is conquered by Ludwig Von Koopa.

7-1
This is a wraparound level, meaning if Mario goes out of one side of the screen, he'll reappear on the other. Plenty of pipes are found here along with plants and koopas.

7-2
The second pipe in the level leads to an underground pool filled with coins, many of which can only be collected by Frog Mario. There is also a P-Switch in the far left end of the pool. After returning back through the pipe, Mario continues walking to the right and jumps over the pit with a crack in it. After a wooden block and a Nipper Plant, Mario must duck in the highest pipe, then make his way to the right-most pipe, going up it. Afterward, he appears in a valley of pipes, above which are many invisible ♩ Blocks which Mario must hit. Afterward, Mario ducks in the pipe to the right, grabs a power-up, comes out, ducks in the pipe to the left, and finally exits the one on the right. Then he crosses the valley on the newly made bridge of ♩ Blocks; on the sixth Block from the left, Mario can jump extra-high to grab a 1-Up. After that, the lowest pipe from the left of the right wall is the pipe leading to the exit pipe.

7-3
This stage is very simple, except for the Lakitu, halfway through however a Starman chain can make this easier. Also, later in the level there is a pipe with unlimited Goombas, which invincible Mario can kill for many 1-Ups. Each of the ? Blocks on the sides of the pipe has a Starman,which can be used to kill some Goombas. Lakitu will then chase Mario.

7-4
This water stage introduces Spiny Cheep-Cheeps. Also, this level boasts a huge maze of Jelectros. The Big Bertha and Blooper Nannys also infest the water.

7-5
This level is a series of rooms. The first and second have nothing worthwhile, but in the third room, hit all the invisible blocks in the gaps in the floor. Then, at the last gap, jump through. The second pipe from the right has a exit not blocked by a block, and if Mario goes all the way to the left and goes in that pipe, he'll be lead to a power-up. After the pipe, Mario must go left, then fall through the second gap and go through another pipe. As a powered-up Mario, he must smash through the blocks to a pipe, then hop in. In this room, Mario must expose invisible blocks to make a solid path on the top, from platform to platform. Right by the pipe at the end, to the left, is a block with a 1-Up. Mario can then exit through the pipe, go across the other bridge he made, then take one last pipe into the out side.

Piranha Plants
This stage is optional, but helpful. Mario must adventure over Munchers and all kinds of foliage. If he has a spare Starman, use it! It'll aid him greatly. The smallest pipe at the end leads to a room with a P-Wing!

Fortress
This nearly-enemyless castle has a very cool secret. If Mario enters powered-up, he can smash away the fourth row of blocks by the metal block, eventually uncovering a P-Switch that when stomped will turn the floor into a coin smorgasbord.

7-6
This is another wraparound stage, but fairly simple.

7-7
This stage is much like the Piranha Plants level, but has, fortunately, a Starman chain. His only hope for beating this stage is to sprint and grab every Starman along the way! Mario must hurry, hurry, HURRY to reach the end before he meets his end. He can let the Stars roam for a bit before grabbing them, effectively heightening his invincibility time.

7-8
This stage has more Piranha Plants and Venus Fire Traps. A Starmen and/or a P-Wing work great here. There is a Starman in the first ? Block, allowing Mario to weed-whack the plants. Plus, the second walking Ptooie guards a pipe to a secret room, which has a Hammer Suit! Use it to smash Mario's way to the exit, and doge fire attacks from Venus Fire Traps and Nipper Plants. Mario also finds a Coin Heaven by jumping and hitting a red jump block.

7-9
This level is a maze of tubing. There are quite a few secrets, and quite a few baddies. Mario can collect coins by smashing the blocks below them. There are many several rich coin deposits in this stage,but the player should watch the timer.

Fortress
Hammer Mario can breeze through this befuddling Fortress, but other Marios might have a harder time. Almost all the Fortress enemies are here. There are lava and pipes too. Boom Boom waits at the end as always.

Piranha Plants
This level is just a remake of the previous one. Mario can jump right over the first stretch of Munchers, and any weapon will mow throw the other plants down. Cross a field of Munchers using sparsely-placed ♩ Blocks and claim the Super Mushroom prize at the end.

Airship
An Anchor is highly recommended, as the Airship can traipse all over the world, and Mario cannot. This Airship has Rocket Engines waiting to singe Mario's rear as he balances on Bolt Lifts. Rocky Wrenches, are here too and Ludwig von Koopa, awaits Mario at the end. Mario can tackle him like all his other siblings, but like Roy, he'll paralyze the plumber by jumping around. Additionally, at the end of the airship Mario will get a letter from Bowser, saying "I kidnapped the princess!"

Trivia

 * The islands of Pipe Land are shaped like Warp Pipes.