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

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

Layout
The player starts along a path with a Koopa Paratroopa leaping towards them. Further on is a square-shaped block formation, with the second brick block from the left containing a Super Mushroom. To get this power-up, the player must strike a block from underneath with proper timing to make the mushroom bounce over the ledge. Up ahead is a row of question blocks, with the one in the middle holding a Poison Mushroom.

After the second pipe and above the tree in the background is a hidden block that holds a 1-Up Mushroom. What follows is a gap and a set of brick blocks. The left-most block has a Superstar, while the block right of the stone stairs is a coin block. The player will need to cross a chasm here by using the upper brick blocks, and while doing so, the player will encounter a row of Koopa Troopas and some question blocks. The third one from the left contains another Poison Mushroom. Next up is a row of enemies followed by two pipes. The second pipe leads to a secret underground area where the player can collect some coins and find some hidden blocks containing either a Poison Mushroom or power-up. Inside the question block furthest to the right, underneath the floating pipe ahead, is a power-up. Following the chasm and pipe leading out of the secret underground area is the stone stairs leading to the goal pole.