New Super Mario Bros./World 7

World 7 is one of two optional worlds in the game, in that it can be skipped entirely when beating the game. This secret world is unlocked by defeating Petey Piranha as Mini Mario or Luigi, back in World 5. World 7 has a sky theme, so many of the courses are high in the sky and have a heavy focus on accurate platforming. It has several Toad Houses, with green ones being the most numerous. It also has a fair amount of secret exits, and at least one must be found to reach the castle.

Level summary

Level	Star Coins
World 7-1	Between two tracks used by the second moving platform. Wait until the platform falls to the lower track before attempting to get it. After passing under a wall of large blocks, jump on to the flying question mark block and ride it until you reach a warp pipe. Go into it to reach a bonus area. Use the ropes to reach the Star Coin. After the checkpoint, stay on the platform moving along the top track and be ready to jump when you pass by the Star Coin.
World 7-Ghost	Go into the top door from the starting room and ground pound the goo to reach the Star Coin. Go into the left door from the starting room. The Star Coin can be obtained by jumping from one of the crests of the wavy goo below. Run right after hitting the P-Switch. When you see some brick block platforms forming steps upward, jump up them to get to the ceiling. Run right to the end for the Star Coin.
World 7-2	The Star Coin can be seen surrounded by brick blocks near the beginning of the lift ride. Simply break the blocks to obtain it. Upon seeing a Star Coin surrounded by blocks, get a shell from a Paratroopa nearby. Throw its shell onto the floor of brick blocks to the left and it will collect the Star Coin for you. Near the exit pipe is a Star Coin surrounded by a swarm of Paratroopas. Move in carefully to grab it.
World 7-3	The Star Coin is above a brick block platform, guarded by a Boomerang Bro. This Star Coin is floating above a pretty high platform. Hop off a Paratroopa or use the wave in the Mega Wiggler's movement to jump up to it. In the flagpole area, ground pound the leftmost brick block to make a vine grow into it. Ground pound any of the other blocks and climb down the vine to find the Star Coin.
World 7-Tower	The Star Coin is located in a pit. Wait until the stone block above it retract into the wall before jumping down and taking it. Jump across several stone blocks with spikes below them to reach an alcove with the Star Coin. At the boss door is a chaotic combination of stone blocks. Look for an opening in the blocks and get to the Star Coin to the left od the door.
World 7-4	Go right from the start until you hit the wall, then use the Spin Block to launch yourself upward. The Star Coin can be found hovering above a mushroom. Jump up from the Spin Block to the right of the first Star Coin, then bounce on the pink mushroom above to reach an even higher platform with the next Star Coin. After bouncing from the tallest pink mushroom, simply hover to the right. The Star Coin should be right in your path.
World 7-5	The first Star Coin is above a brick block walkway. You must bounce off a Bullet Bill to break the blocks and get on the walkway, or just cause the Bob-omb to explode, leaving a gap for you to jump through. There is a mini warp pipe sealed with a single block. Use a Bob-omb to destroy the block and go into the pipe. In the bonus area, go right and hit the block to make a Mega Mushroom appear, then go left and force the pipe above the Star Coin right to obtain the coin. This Star Coin is located between two Bullet Bill Launchers. The Bullet Bills are obvious hazards here.
World 7-6	The Star Coin is hovering in midair just before the pipe leading to the red flagpole. Jump up from the moving mushroom platform to get it. Two Paratroopas guard a Star Coin located inside an alcove that can be found soon after the checkpoint flag. After the checkpoint, enter the only yellow pipe up ahead to reach a secret area. You must bounce off the three Paratroopas to your right to get on a mushroom platform below a pipe. Go into the pipe to collect the coin.
World 7-A	Through a horizontal pipe at the very bottom of the maze is the Star Coin. Jump to the right of the red block platform to reveal hidden blocks to the pipe entrance. Look for a cannon pipe at the right wall on the second level of the pipe maze. After launching yourself up, cling to the wall on the right and jump to the warp pipe entrance when you pass below it to reach a room with the Star Coin. On the same level as the block where you got the Mini Mushroom, go left and wall jump up the thin gap between the two pipes to enter a mini warp pipe, which takes you to a secluded area with the Star Coin.
World 7-7	The Star Coin is located at the end of the first rotating platform's track. After riding the platform with the erratic track, get on a donut lift and wait for it to fall, then jump as soon as you get the Star Coin. This coin can be found floating to the upper-left of the donut lift pyramid after the checkpoint.
World 7-Castle	This coin is floating near the air above the first set of spikes. Simply jump up when the Snake Blocks are near it to obtain the Star Coin. The final swinging Ball 'n' Chain has a Star Coin on the block it's circling around on. The last Star Coin is just off the edge of the final platform. Wait until you're falling with the Snake Blocks, then jump on to the platform to get it.

Secret exits

World 7-Ghost

After hitting the P-Switch, try running to the left instead. As you pass by some brick blocks overhead, look for one block that has a glimmering effect. This signifies that the brick block is actually a disguised question mark block, and hitting it causes a vine to grow. Get on to the block before the other brick blocks revert to coins, then climb up the vine to reach an alcove with a door. The door leads to the secret exit of the ghost house, where the red flagpole can be found.

This secret exit creates a shortcut to the World 7-Tower, skipping two levels while opening a green Toad House for you to use.

World 7-4

You'll need to be in your Mini form for this secret exit. Once you've bounced from the tallest pink mushroom, look for a flying block near a wall to your left and land on it. Jump to the narrow alcove, then make a jump to loop around the wall above the alcove and drop into the small valley with the mini warp pipe. Take the warp pipe to get to the red flagpole.

This secret exit skips straight to the World 7-Castle, letting you skip the confusing network of levels that comprise the second half of World 7 and opening a green Toad House as well.

World 7-5

Right before the Banzai Bill Blaster, there is a small hill of brown blocks covering the entrance of a warp pipe in the ground. The lone Bob-omb can't destroy enough blocks to let you access the warp pipe, so you have to get the Bob-omb before it to the right of the rotating Bill Blasters, and use both Bob-ombs to make a large enough hole to reach the pipe. If positioning Bob-ombs while being fired on from all sides is two difficult for you, you can simply use a Mega Mushroom to tear through the blocks. Once the warp pipe entrance is available, go into it to enter a cave. Go right and up the right warp pipe to be taken to the red flagpole.

This secret exit creates a path to World 7-A, just one of several paths to the castle in the convoluted second half of World 7.

World 7-6

After the checkpoint, there are two brick block platforms arranged parallel to each other, with Paratroopas hopping underneath. First, you must destroy the middle brick block of the top platform. Then, hit the middle block of the bottom platform from below to make a vine grow into the sky. Climb up it to reach a bonus area. Get on the mushroom to make it move. Stay on the mushroom as it goes toward the right. You can make small jumps to get coins, including the first Star Coin of the stage. Eventually, you will reach a thin platform with a pipe above it. Go into the warp pipe to arrive at the red flagpole.

This secret exit creates a path to World 7-7, one of three paths that allow you to continue onward to the castle.