Fortress

Fortresses or Forts are fortified buildings first found in Super Mario Bros.. After reaching the Fortress, Mario or Luigi can advance to the next level. At the end of a world, a False Bowser can be faced.

In Super Mario Bros. 3, they are called Mini-Fortresses, and are usually found in the middle of worlds. They are guarded by Boom Booms and must be defeated to gain access to other parts of the world. Later, in Super Mario World, Fortresses are guarded by Reznors and most of them are optional.

Forts are also boss levels in Super Mario World 2: Yoshi's Island. They act like the mini-boss levels of each world.

The Fortresses later return in New Super Mario Bros. and New Super Mario Bros. Wii and reprise their roles from Super Mario Bros. as allowing Mario or Luigi to continue to the next level. In New Super Mario Bros. Wii, at the end of every Fortress, there is a boss fight with a Koopaling of that world. After defeating it, it flees to the castle at the end of its respective world for a rematch. In World 8's Fortress, instead of a Koopaling found at the Fortress (since the seven of them have already taken over the previous seven worlds' Fortresses), Kamek is fought at the end, but he does not flee when he is defeated like the Koopalings, for there is no other castle bar Bowser's Castle. Each Koopaling's fighting area at the end of each Fortress is described below:
 * World 1: The fight with Larry Koopa is extremely simple, with small bottomless pits on each side of the room.
 * World 2: Roy Koopa has a fight which is over a pit of quicksand.
 * World 3: The fight with Lemmy Koopa is on a floor of ice with two bottomless pits on each side.
 * World 4: Wendy O. Koopa has a fight in a small room, similar to both her original fight in Super Mario Bros. 3 and Bowser Jr.'s in New Super Mario Bros..
 * World 5: Iggy Koopa's battle has three shifting platforms.
 * World 6: Morton Koopa Jr. has his fight over a pit of lava, with spiked Pillars crashing down onto the side platforms.
 * World 7: Ludwig von Koopa's battle has bottomless pits on each side like Larry Koopa.
 * World 8: Kamek is fought on platforms coming in from the right of the room.

Appearances in Other Media
In the Mario Ice Capades, during the whole show, King Koopa rode a fort that was surprisingly a moving one. A fort also appeared in the background of the show as a prop.