Factory (Super Mario RPG: Legend of the Seven Stars)

The Factory (also known as Smithy Factory) is the gloomy dimension where Smithy and his cohorts resided during the events of Super Mario RPG: Legend of the Seven Stars. The entire factory was filled with Smithy's Machine Made weapons and the assembly lines that carried them. The factory's design greatly resembles that of the Airships of Super Mario Bros. 3, including the Bolt Lifts sometimes utilized to reach far platforms and the fog that fills the air. Mario, Mallow, Geno, Bowser, and Princess Toadstool fought many hard battles and endured countless perils during this last leg of their journey.

Unlike other worlds of the Mario series, like Earth, the Mushroom World itself, or Subcon, which are filled with wonder, the Factory is seemingly little more than a nightmarish, dark void filled with mechanical beings and bizarre, sinister creatures.

Smithy Factory also refers to World 7 of the game. This region includes the Factory dimension as well as the gateway to Mario's dimension, in this case, the Smithy Gang-occupied Bowser's Keep and Vista Hill.

Underground Interior
After defeating a Machine Made Yaridovich, a Brick Block will explode to open a passage deeper underground. This leads Mario and company directly to a boss battle against Cloaker and Domino and their pet snakes, (either Mad Adder or Earth Link, depending on which of the bosses is left standing).

The inner part of the factory is seemingly made of all steel, even the floors. To the right, in each room, Mario can witness the process of a Jabit being manufactured. Also, various factory workers in charge of each department will try and fight off Mario to try to prevent him from getting to Smithy.

Trivia

 * According to a Shyster the factory was built "yesterday" and the foundation is "very weak".
 * The music has a very complex time signature of 13/8 (13 quavers [eighth notes] to a bar [measure]).