Rogueport Sewers
Rogueport Sewers is a huge chain of rooms under Rogueport that contain the Thousand-Year Door, various Warp Pipes, and the Pit of 100 Trials. There is a hidden town here with a shop that sells rare items such as Ultra Shrooms and Gold Bars. Hidden in the sewers is a Teleportation Device that the X-Nauts used to teleport from X-Naut HQ to Rogueport. The main way of getting into the sewers is a pipe in front of Professor Frankly's house. Another way in is West Rogueport's sewer grate. Special blue pipes leading to Petal Meadows, Petalburg, The Great Tree, Twilight Town, Keelhaul Key, Poshley Heights and Fahr Outpost can be found in the sewers.
Other Notes
A few houses in the background can be entered by special warp pipes.
The Thousand-Year Door in the Rogueport Sewers is directly below the gallows in Rogueport Square.
The Rogueport Sewers is to Paper Mario: The Thousand Year Door as Toad Town Tunnels is to Paper Mario.
