World D-3

World D-3 is the third level of World D in Super Mario Bros.: The Lost Levels and the nineteenth secret level overall in said game. The darker fortress walls in the background appear in the original version of the game with items being found in bricks, but the walls are absent in the Super Mario All-Stars version, with items being found in Hidden Blocks.

Layout
The player starts next to a group of six Turtle Cannons, and in the third gap between them is a brick with a power-up. After a pipe with a Piranha Plant, there are two Hammer Brothers. that will charge at the player. Before the next Turtle Cannon, there is a row of Hidden Blocks that can be used as cover against the next group of Hammer Brothers After another group of six Turtle Cannons is a Springboard that the player can use to reach the top of a pillar with a Red Koopa Troopa on it, which can be used to defeat the Hammer Brother below. Next is another Piranha Plant, three more Turtle Cannons, two Hammer Brothers, and a Koopa Paratroopa before Turtle Cannons in a stair formation that lead to the flagpole.