The Thousand-Year Door

"It's the Thousand-Year Door spoken of in the legends! I can't believe it's real!"

- Professor Frankly

The Thousand-Year Door is a massive door in Paper Mario: The Thousand-Year Door that is said to have a treasure behind it. Generations of locals have created myths about what is behind it, and nobody knew that it turned out to be the entrance of the Palace of Shadow. The only person that knows Rogueport's true history is Grifty.

The Thousand-Year Door, like the Crystal Stars and the Palace of Shadow it leads to, was created to hold back a horrifying demon that had destroyed the town that once stood within Rogueport's boundaries. The four heroes' designing made it so that the Crystal Stars were required to open this door, although their seal on the door would last for only a thousand years and was therefore continually weakening before the events of the game. When Mario places all seven Crystal Stars before the door, the dark power causes the door and walls around it to crack. A vortex spews out, and the entrance to the Palace of Shadow is opened. The so-called treasure that had been spread in rumors is revealed as the Shadow Queen herself, but the ending shows a Dried Shroom. Its discoverer, Professor Frankly, is still happy with his finding, because it is proof that civilizations ate mushrooms 1,000 years ago.

Because of the legends surrounding it, very few people have even dared to touch the door.

During the fight with the Shadow Queen, the pedestal in front of the door is shown to be directly underneath the center of Rogueport (the gallows). During the long cutscene halfway through the battle, the player sees, around the gallows, the pedestal's lights, as well as each of the Crystal Stars.

Trivia

 * A Sammer Guy in Super Paper Mario is called Thousand-Year Roar, referencing either the Thousand-Year Door itself or Paper Mario: The Thousand-Year Door's subtitle.
 * In the final scene in which the player takes control of Bowser, Kammy Koopa immediately recognizes the Thousand-Year Door and its rumored treasure when Bowser asks what it is. Kammy seems to be the only non-Rogueport resident who knew of the Thousand-Year Door before the events of the game.