World 6-1 (Super Mario Bros.: The Lost Levels)

World 6-1 is the first level of World 6 in Super Mario Bros.: The Lost Levels and the twenty-first level overall in said game.

Layout
The player starts next to some block formations. In the first Brick Block is a power-up, the last Brick Block of the second formation contains a Super Star, and above the Koopa Paratroopa in the second formation is a hidden 1-Up Mushroom. After a row of enemies ending with a Hammer Bro is a tall pipe with a Piranha Plant with a Hidden Block directly to the left of it that will help the player get over. After the tall pipe is a Bill Blaster before a large pit with a staircase on the other end. Next is both ground and hanging pipes with Piranha Plants and a Hammer Bro, followed by a couple of Koopa Paratroopas coming at the player. In the row of ? Blocks above, the fourth from the left contains a power-up and the second from the pipe contains a Poison Mushroom. Through the two pipes is a tall staircase and wind will start to blow as the player jumps up it. Below the staircase is a Warp Pipe that leads to an underwater area with Coins, Bloopers, Koopa Troopas, and lifts that push the player down into the currents. Past the staircase are lifts that will fall once the player lands on them, followed by a Piranha Plant and a horizontally moving lift before the pipe that the underwater area exits from. Here, the wind will stop blowing, and the player then needs to climb up pipes with Piranha Plants before they can reach the Goal Pole.

Level statistics

 * Power-ups: 3 (Two Super Mushrooms or Fire Flowers and one Super Star)
 * 1-Up Mushrooms: 1
 * Poison Mushrooms: 1
 * Secret areas: 1