World's Largest Dungeon
The World’s Largest Dungeon is a Dungeons & Dragons adventure set entirely in an enormous dungeon. It is over 800 pages long and was produced by Alderac Entertainment Group in 2004. It also includes 16 full-color poster maps, making its single tome one of the largest campaign settings in one product.
The players can’t leave the dungeon the way they entered because the entrance uses a one way wall of force effect. This means that all supplies must be taken into the dungeon with them. The campaign is designed to take four to six characters from first level to 20th or above over the course of two real-time years and at least a year of game time. The dungeon contains examples of every type of monster in the System Reference Document  as well as a few new ones.