World 5-1 (Super Mario Bros. 3)

World 5-1 is the first level in Sky Land from Super Mario Bros. 3.

Layout
The player starts in an area with a single Buster Beetle, some Brick Blocks, a Hard Block containing a power-up, and a Chain Chomp. If the player has a P-Wing, or is powered-up with a Super Leaf or a Tanooki Suit, they can fly to a Warp Pipe leading to a secret area with a chest containing a Music Box, which can be accessed by crouching and flying to a small gap on the right or running across while small, and another Warp Pipe that leads the player to an area below the main level with four 1-Up Mushrooms. Above there are three Brick Blocks, one of them with a P-Switch, which makes two numbers (three and four, or two threes in the NES and SNES versions) made of coins appear. After that, there are some Nipper Plants, another Buster Beetle and two more Chain Chomps, guarding some ? Blocks, one of them holding a Super Star. Afterwards, there are more Nipper Plants and a Paragoomba, followed by some Brick Blocks and the goal.

Enemies

 * Buster Beetles
 * Chain Chomps
 * Nipper Plants
 * Paragoomba

Level statistics

 * Power-ups: 3 (Super Mushrooms or Super Leaves and one Super Star)
 * 1-Up Mushrooms: 4
 * Secret areas: 1

Trivia

 * In the original Japanese Famicom release, the main level ends in a pipe, with the goal being in a sublevel. However, because that sublevel also contains the secret area, this leads to a glitch where Mario can trigger the chest into appearing. The Nipper Plant and items in the goal box will then appear glitched, and once Mario gets a card, another chest spawns in a random spot. If it spawns where Mario can get to it, the "Course Clear! You Got a Card" text also appears glitched. The chest contains a fourth Recorder.
 * Unusually, in the Super Mario All-Stars version of this level, the Chain Chomps are depicted as having blue mouths.