Dark Land

Castle of Koopa (also known as Dark Land or Bowser's Castle) is the eighth and final world in Super Mario Bros. 3, but it is possible for the player to obtain two Warp Whistles from World 1 and use them to reach Castle of Koopa without having to play through the other levels. Castle of Koopa is a sinister land where volcanic clouds cover the skies and block out the sun's light. One of the areas in the map is so dark that it appears to be completely black, except for a circle of light around Mario or Luigi.

Castle of Koopa is Bowser's kingdom, and is the place where his main castle stands. It is also the Koopa Troop's main base of operations, and because of this, the area is heavily defended by the Koopa King's military forces. Large numbers of tanks and airships patrol these lands, intercepting anyone brave enough to invade the kingdom.

Bowser's Tank Force (Big Tanks)
The large tanks are similar to airships, only on they are on the ground. Here, the player will meet up with Rocky Wrenches, cannons, and Rocket Engines. There is also one power-up in this level. At the end of the level awaits a blue Boomerang Bro..

In Super Mario Advance 4: Super Mario Bros. 3, this level was made shorter by removing two of the tanks that came after the ? Block.

Bowser's Navy (Battleships)
These battleships are similar to tanks, only in the water. As these are in ordinary water, Mario (or Luigi) will not be hurt if he jumps in. After avoiding obstacles and enemies, Boom Boom awaits at the end of the level. One can actually swim under the ship for the entire length of the level and emerge unscathed.

Hand Traps

 * 1) This contains every Hammer Bro. variety found in the game. The level starts with a Fire Bro. After it, there are two Hammer Bros. ready to attack. Also, there is a power-up in one of the blocks. A Boomerang Bro. awaits further into the level. The final enemy, a Sledge Bro. is encountered towards the end of the level. Once past there, the player can go up the pipe to claim a Super Leaf.
 * 2) The player must jump over Podoboos and leap onto platforms to reach the end. A Super Leaf is at the end of this level.
 * 3) The player must avoid jumping Cheep Cheeps in this level. At the end there is a Super Leaf.

Bowser's Airforce (Airships)
A ton of tiny, Rocket Engine-equipped jets patrol the night sky. Rocky Wrenches are found on most of the jets. At the end, Boom Boom awaits to battle. After the player attacks Boom Boom twice, it'll start to fly. Most of the ships have the same form.

At the start of the level, there is a Switch Block in the air, which reveals many blue coins closer to the ground. The player can use a Super Leaf or Tanooki Suit to fly from the very first platform to a pipe way up high where three 1-Ups are. Further into the level, a ? Block near a Venus Fire Trap's pipe withholds a power-up. A row of bricks is soon found. In between the tall multi-Bill Blasters, within a ? Block, there is a Starman. A hidden 1-Up Mushroom can be found within a long line of blocks. Then, the player must use a red Koopa Paratroopa to leap over a very tall Bill Blaster. The player can jump out between the two Blasters. The Jump Block nearby will send the player across the gap. After this, the player needs to leap over the Piranha Plant and the level will be completed.

At the beginning, the player can either fall through the quicksand or enter one of the pipes, or jump over the quicksand. In the latter case, this level is the second and final to feature the Angry Sun, which is very rare. The player must avoid multiple Venus Fire Traps; eventually, a block containing a P-Switch can be found. After the ♩ blocks hovering over a pit, the player must ascend and descend the Venus Fire Trap populated hill. After the hill comes a small pit with one ♩ Block. The player must leap off a Koopa Paratroopa and bounce on the Note Block to reach the exit.

The level starts out with an area with blocks and a door. Further on, the player must maneuver on conveyor belts; however, there is lava below. To the left is a power-up, needed to complete the level. The player must repeat this process until he has secured a Super Leaf, which is to break the bricks to the right. To the right, the player must avoid the Thwomp and smash a way through the blocks. Next, the player must enter the third door to the right, entering the next room; here, the player must avoid the Thwomps moving diagonally. Then the player must enter another door. Then, the player has to keep right, entering the door placed on the metal blocks. The player must then press the P-Switch and run right, entering the door at the end without stopping. After coming out of the door, the player has to keep moving, until two coins, unmoving, wedged between the metal blocks and a conveyor belt, are spotted. The player must wait until the P-Switch wears off, sneak under them, and hit the right one for a P-Switch again. The player can then enter the door that appears to the farthest right. Then, the player must wait again for the P-Switch to wear off, and duck as the belt carries the player safely under the spike battle Boom Boom.

Bowser's Army (Super Tanks)
The player must avoid Bob-ombs, Rocky Wrenches, and other hazards on these huge tanks. At the end, Boom Boom will battle the player for the final time.

In the final level of the game, Bowser has set up several traps. Near the start, statues with laser vision attack in place; if the player jumps over them, he or she can reach brief safety. Then, ride the platform up, taking the Donut Lift down. Here, ascend the staircase, avoiding the Roto-Discs. At the top the player must go back down to the ground on the other side. Alternatively, there is an extra life at the top right of this section, in a hidden block. If the player ducks and jumps on top of this block, they will float through the wall, skipping the descent. Afterward, a lake of lava with Donut Lifts and Podoboos looms. In an alternate route, the player can go up and head right. If the player keeps heading right, avoiding the pool of lava and dodging fireballs, a door awaits. Once again, there is a room with statues and fireballs. Then, the player must go through the door at the far left. This is where the battle with King Koopa takes place.

King Koopa can be defeated with either hitting him with many fireballs or 4 hammers. In battle, the Koopa King will leap up occasionally, crashing down into the weak floor, making an indent. King Koopa's only other attack is his ability to breathe fire. If King Koopa breaks through the whole floor, he's defeated. The door to the right will open and flash. Enter to find a distraught Princess Toadstool. She'll thank the player, then scamper off. The game ends and the credits scroll.

''The Adventures of Super Mario Bros. 3
As it is home to Bowser and the Koopalings, Dark Land appears in quite a few episodes of The Adventures of Super Mario Bros. 3, where it is depicted as a gloomy wasteland. Lava-filled caverns are shown to be beneath the surface of Dark Land in a few episodes as well. However, most of what goes on within Dark Land happens either near or inside Kastle Koopa. Not counting episodes in which all the Dark Land scenes were restricted to events within the permiters of Kastle Koopa, Dark Land appears in the following episodes:

Reptiles in the Rose Garden: In order to give Kootie Pie rulership of the United States of America as a birthday present, Bowser transports the White House, along with everyone inside, to Dark Land. Bowser later sinks the White House to the bottom of the Mushroom Sea. However, Mario managed to raise the White House to the surface, and with Luigi's help, was able to return the building to its proper spot to Washington, D.C..

Mind Your Mummy Mommy, Mario: Luigi, Princess Toadstool and Toad travel through Dark Land via a Steam Cloud Balloon to recover Prince Mushroomkhamen's stolen sarcophagus, only for it to get flung into a tower of Kastle Koopa by a Mushroom Kingdom Twister. Luigi then uses the remnants of the Steam Cloud Balloon to construct a Steam-Powered Mummy Sled, which he, Princess Toadstool and Toad use to escape from Kastle Koopa, and subsequently, Dark Land.

Princess Toadstool for President: After discovering that Bowser in ahead in the polls for leadership over the Mushroom Kingdom only by using a Nice Guy Potion, Mario and Luigi travel to Dark Land in order stop Kooky and Cheatsy from making another dose before the election. Upon arriving in Dark Land, Mario and Luigi are purused by Rocky Wrenches in tanks, which chase them through a pipe into a lava-filled cavern. From that point, Mario and Luigi then have to deal with Fire Chomps, Hot Foots and a Fire Snake before making it to Kastle Koopa.

Never Koop a Koopa: When Bowser announces that he's giving up his evil ways, he donates Kastle Koopa to Princess Toadstool. Wanting to turn Kastle Koopa into a retirement home for elderly Mushrooms, Princess Toadstool travels to Dark Land with Mario to check the place out. However, Luigi is wary of the whole thing. He and Toad travel to Dark Land after Mario and Princess Toadstool, where they wait in a boat on the Mushroom Sea for their friends to return from Kastle Koopa. When Mario and Princess Toadstool fail to come out after waiting for a long time, Luigi forcefully drags Toad through the Mushroom Sea and enters Kastle Koopa via a drain pipe. While the whole ordeal turned out to be a trap, the group of four later escape from Kastle Koopa after obtaining Raccoon Power.

Do the Koopa: Princess Toadstool discovers a map leading to the Doom Dancer Music Box, which is hidden in the underground Temple of Gloom. Mario, Luigi and Toad accompany Princess Toadstool to Dark Land, but they are immediately spotted by a Dry Bones, who heads to Kastle Koopa to warn Bowser of their arrival. As Bowser is sick, he orders Bully Big Mouth and Cheatsy to follow the Dry Bones, who leads them to where the heroes are travelling. Mario's group brave the cavern's many traps and ultimately make it to the Temple of Gloom, where they succeed in obtaining the Doom Dancer. However, a trap set up by Bully causes Mario to lose the Doom Dancer, which winds up in Bully's hands. Bully then brings uses the Doom Dancer's power to bring everyone back to Kastle Koopa, where Bowser, who is unable to hear well due to his cold, takes the Doom Dancer from Bully. Bowser then uses the Doom Dancer to force everyone in the Mushroom World to dance forever, but the Mario Bros. foil his plan.

The Venice Menace: Although Dark Land is unseen in this episode, Bowser's intention is to scare all the humans out of Venice so that he can warp the entire city to Dark Land and turn it into a water park for Kootie Pie.

''Nintendo Adventure Books
Dark Land is the setting of the fourth Nintendo Adventure Book, Koopa Capers, where Bowser has a Magic Carpet bring Luigi to the kingdom to help (whether he wants to or not) in the search for Wendy O. Koopa after the Koopaling disappears. The two main areas of the region that can be explored in the book are a gloomy and trap-filled fortress, and a highly volcanic area known as the Magma Pits.

In the proceeding book, Pipe Down!, Dark Land (though here referred to as Dark World) is mentioned once by Ludwig von Koopa, who states that he intends to take his new opera, Dribbling Beauty, on a seven year tour of the kingdom.

Trivia

 * Dark Land's music bears some possibly intentional resemblance to the Mars movement of The Planets, fitting as this movement is subtitled "The Bringer of War" after Mars, the Roman god of war.
 * The lava in the first area of World 8 looks like red water in the NES version.
 * Dark Land is the only world in the game that does not have any Toad's Houses, Hammer Bros. patrolling the map, and Spade Panels in it.
 * In the Japanese versions, Dark Land is known as "Castle of Kuppa". In the initial worldwide NES release and English Super Mario All-Stars, this was corrected to the standard Castle of Koopa. It was also called Bowser's Castle in the Game Boy Advance version. It is only known as Dark Land in the international NES re-release and supplemental materials.
 * In the Bowser's Navy level, the player can simply swim under the ships to get to the boss, safely bypassing all of the hazards. This has been fixed in Super Mario Advance 4 where the stern of the last ship has been made one block higher to discourage players from using that shortcut by forcing them into an unfavorable situation where they cannot get back on the ship and have to self-destruct.