World 6-1 (Super Mario Bros.)

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

Layout
The player starts on a small stretch of land with two ? Blocks. Across a gap are some stone stairs, a Lakitu above, and two Brick Blocks with the left one containing a power-up. In the right Brick Block of the next formation is a Coin Block. Across some gaps and two sets of stone stairs, the second of which is broken with a floating platform, the player will come across two rows of Brick Blocks. Directly to the right of the stone stairs under the top row of blocks is a Hidden Block with a 1 up Mushroom. After a pipe with a Piranha Plant are two stacked Hidden Blocks above the background hill that can be used to defeat the Lakitu that appears here if the player defeated the first Lakitu. In the left ? Block up ahead is another power-up, and in the right Brick Block of the middle row up ahead is a Coin Block. After a flight of stone stairs and a stone pillar is the flagpole.

In Super Mario Bros. 35 prior to the version 1.0.2, the Hidden Block containing 1 up Mushroom, the highest step of the staircase before the block, and three Brick Blocks above the block were lowered by one block.

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 Hidden Block at the top of the castle at the start of the level, the player needs to jump to find Hidden Blocks located to the right of each floor of the castle, and the score to beat is 32000. The Red Coin locations are:
 * Underneath the floating set of stone stairs
 * In a new Coin Block, located in the left Brick Block of the bottom row where the 1 up Mushroom can be found.
 * To the right of the top Hidden Block after the pipe
 * To the right of the second group of ? Blocks
 * In the Coin Block before the end of the level

Level statistics

 * Power-ups: 2 (Magic Mushrooms or Fire Flowers)
 * 1 up Mushrooms: 1
 * Secret areas: 0

Mondo 6-1 (Super Mario Bros.)