World 1 (Super Mario Bros.)

World 1 is a world in the Mushroom Kingdom in Super Mario Bros. It is the first world in the game.

World 1-1
The original World 1-1 from Super Mario Bros. has been re-created in many games, including Super Smash Bros. Brawl, where it appears as a stage named Mushroomy Kingdom.

World 1-1 contains the basics of the Super Mario Bros. game, getting the player ready for the journey ahead. The level consists of Super Mushrooms, standard enemies such as Goombas and Koopa Troopas, a lot of Coins, a hidden secret bonus area, Fire Flowers, deadly gaps, and a flagpole at the end.

Description
World 1-1 starts out on a brick path, possibly a path that was once a walkway in a town of the Mushroom Kingdom before King Bowser's violent coup. As Mario moves forward, a Goomba appears and starts walking toward Mario. The red-clad plumber also reaches the the memorable first ? Block and then the six block triangle formation of ? Blocks and regular brick blocks (with a Super Mushroom inside the left block). A set of Pipes await Mario with Goombas located in between the plumbing. The final pipe among the set leads to a bonus area of coins and can be entered to warp through the level. After that, there is a gap followed by a ? Block containing a Fire Flower inside. Additionally, Goombas start falling down from a long row of blocks above.

Afterward, a block down below contains ten Coins that Mario can retrieve by Jumping repeatedly (at the right time) underneath the brick. Then there is the notable ? Block triangle formation, which contains no regular blocks. The top block contains a Fire Flower (or a Super Mushroom if Mario is regular instead of Super Mario). Upcoming are some more Brick and ? Blocks, followed by a pyramid-like set of unbreakable blocks with a gap in the middle. After that is another set of unbreakable blocks, this time with a gap in the middle that Mario can fall into and get killed. Just following is another pipe that is unenterable, accompanied by two Goombas and a set of ? Blocks with coins inside.

Lastly, Mario reaches the Ending Staircase for the level, and the Flagpole afterward.

Interestingly, this level had no Piranha Plants coming out of pipes. 1-2 This is the first underground level in Super Mario Bros. It starts out with Mario(or Luigi) going through a pipe in the over world. They go underground until the end of the level when they get out and jump the flagpole. Since it's dark underground, the goombas are blue.

Trivia

 * A license plate in the Mario Kart: Double Dash!! course Mushroom City, has "W 1-1" written on it. This is a reference to World 1-1.