World 7-A

World 7-A is the only secret level of World 7 in New Super Mario Bros.. This level is unlocked by finding the secret exit in World 7-5.

Layout
This level starts on land. The player must go through the pipe to enter an underground pipe maze area. There, Mario will go through several pipes to eventually reach the top. The pipes contain several Piranha Plants and there are also many Squigglers that will be found throughout the area. At the top right of the area, the player will go through the pipe to find the flagpole.

Star Coins

 * Star Coin 1 - At the beginning of the area, Mario must hit three invisible coin blocks and then go into the pipe to find the Star Coin.
 * Star Coin 2 - Mario must shoot himself up by using the Pipe Cannon and then wall-jump and go up the pipe to find the Star Coin.
 * Star Coin 3 - Near the end of the level, the Mini Mushroom must be used to go up the pipe in the top left corner.

Enemies

 * Squiggler
 * Piranha Plant
 * Koopa Troopa