FAQs What is the World's Largest Dungeon? The World's Largest Dungeon was a 3.0 supplement put out by Alderac Entertainment Group (AEG) back in 2004. It touts a whole bunch of gimmicks ("All the monsters from the Monster Manual!"), but all you really need to know is that it's one Hell of a dungeon crawl.
Is there any plot? Technically yes. The first few pages have "reasons you might go here", including a couple amusing tables you can roll on for random reasons. Each region also has its own little metaplot, but few of them are connected in the "vanilla" game.
That sounds boring.
And it can be, if all you treat it as is a standard dungeon crawl. What made it awesome when I ran it for my home group was the emergent story. They took little things and made them into region-spanning stories.