The Lost City of Barakus is a campaign setting and adventure module designed for 1st to 5th level characters using the D&D 3.0 ruleset.
From the Book: "Players can attempt to stop the city beggars from being sold as slaves, face bandits in the wilderness, expose the corruption of a noble family, destroy an ancient evil, and explore mysterious caves containing the remnants of a ruined civilization.
The book details a complete city, the wilderness surrounding it, and a huge, 5-level dungeon from a long-forgotten civilization. Dozens of minor quests and puzzles are used to distract and entertain adventurers while the main storyline builds to a crescendo. This adventure and sourcebook contains over 30 highly detailed side quests that take place in the wilderness and city, and the dungeon itself contains over 200 numbered encounter areas."