World 1-1 (Super Mario Bros.)

World 1-1, also known as Course 1-1 in Super Mario Bros. 35, is the first level of World 1 in Super Mario Bros., and the first level overall in said game; thus, it is the first level in general of the entire Super Mario series. The first screen of the level is also the game's title screen when starting it up. It contains the basics of the Super Mario Bros. game, getting the player ready for the journey ahead. The level consists of Magic Mushrooms, standard enemies such as Little Goombas and Koopa Troopas, a lot of coins, a hidden secret bonus area that allows the player to skip most of the level, Fire Flowers, pits, and a flagpole at the end. According to Shigeru Miyamoto, World 1-1 was one of the later levels created, due to the "fun" courses created first being more suited for late game, where players were more familiar with how Super Mario Bros. works.

Due to its iconic notability, the level has been re-created in many games, including Super Mario Advance 4: Super Mario Bros. 3, New Super Mario Bros. Wii, New Super Mario Bros. 2 (as part of the first stage of the Gold Classics Pack), Super Smash Bros. Brawl, Super Paper Mario, NES Remix 2 (recreated in Super Mario Bros. 3's engine similar to Classic World 1-1, as the first of the Bonus stages), Super Mario Maker for Nintendo 3DS (as the first level of Super Mario Challenge), in a theater in the Metro Kingdom of Super Mario Odyssey, and Super Mario Maker 2 as the 4-star difficulty level Super Mario Bros. W1-1?.

Layout
This level starts out on a brick path. As Mario or Luigi moves forward, a Little Goomba appears and starts walking towards them. They then reach the first ? Block of the game, and afterward the six block triangle formation of ? Blocks and regular Brick Blocks (with a Magic Mushroom inside the left block). A set of Pipes can be found, with Little Goombas located in between them. The final pipe among the set leads to a bonus area of coins and can be entered to bypass much of the level. After that, assuming the pipe was not taken, there is a hidden 1 up Mushroom block and a pit followed by another ? Block containing an item, possibly a Magic Mushroom or Fire Flower, depending on the their form. Additionally, Little Goombas start falling down from a long row of blocks above. There is a Brick Block down below contains ten coins that the plumbers can retrieve by jumping repeatedly underneath the brick. There are two Brick Blocks after that; the second one contains a Starman. Then there is a ? Block triangle formation. The top block contains a Fire Flower (or a Magic Mushroom if Mario is small). A Koopa Troopa and more Little Goombas appear. Brick Blocks and ? Blocks can be found, followed by a pyramid-like set of Hard Blocks with a gap in the middle. After that is another pyramid-like set of blocks, this time with a pit in the middle. Just following is another pipe that cannot be entered (which is the exit from the bonus area mentioned earlier), followed by two Little Goombas and four blocks in a row (three Brick Blocks and a coin-holding ? Block). Afterwards is another inaccessible pipe, the ending staircase for the level, and the flagpole, which is reused in all underground and underwater stages in the game.

Super Mario Bros. Deluxe challenges
In Super Mario Bros. Deluxe, Mario or Luigi 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 within the first set of pyramid-like steps, and the score to beat is 32000. The Red Coin locations are:
 * On the row of blocks at the start of the level.
 * In the first ten-coin block after the second pit. The player needs to collect all the coins first before the Red Coin appears.
 * In the third ? Block soon after the second Red Coin.
 * On top of the Brick Blocks soon after the third Red Coin. The player needs to use the single Brick Block as a platform.
 * In the final ? Block of the level.

Trivia

 * A license plate in the Mario Kart: Double Dash!! course Mushroom City has "W 1-1" written on it, referencing World 1-1. The same license plate can be seen on cars in Moonview Highway in Mario Kart Wii.