World 3-1 (Super Mario Bros.)

World 3-1 is the first level of World 3 in Super Mario Bros. and the ninth level overall in said game. Notice the silver BG. This stage marks the debut of the Hammer Brother enemy in the series. The Koopa Troopas that walk down the staircase at the end of the level are frequently used to do the infinite 1-Up trick.

Layout
The player starts off next to some ? Blocks, with the right-most block containing a power-up, and Koopa Paratroopas jumping toward the player. Across a gap and some pipes (the second of which leads to an underground area with some coins and another power-up, and exits out to the fourth pipe) is a bridge with some Little Goombas, and above the bridge is a Hidden Block with a 1 up Mushroom. In the left-most block of the Brick Block formation afterward is a Starman, that can make getting through the Hammer Brothers up ahead easier. In the second ? Block on the block formation with the Hammer Brothers is a power-up. A jumping board afterward can help the player get over the Brick Blocks ahead, and the right-most block on the top row has a beanstalk that leads to Coin Heaven. Next is a set of stone stairs with Little Goombas walking down them, followed by a group of blocks and enemies, with the bottom-right ? Block containing a power-up. In the row of blocks afterward, there is a Coin Block in the second block from the left. Finally, there is a stone pillar followed by some Koopa Troopas walking down the stone stairs before the flagpole. The Koopa Troopas can be used for the "Infinite Lives" trick.

Super Mario Bros. Deluxe challenges
In Super Mario Bros. Deluxe, the player can collect five Red Coins, find a hidden Yoshi Egg, and get a medal based on their score. The Yoshi Egg is found in a Brick Block underneath the beanstalk, and the score to beat is 45000 (40000 in the Japanese version ). The Red Coin locations are:
 * In the middle of the first row of Brick Blocks
 * In the opposite block of the power-up in the underground area
 * In the ? Block on the left at the Hammer Brothers area
 * In the top-left ? Block in the group of ? Blocks
 * After the stone pillar