Dungeons & Dragons creators Dave Arneson and Gary Gygax built their campaigns around huge dungeons that grew and changed. Megadungeons span enough rooms and levels to become the focus of an entire campaign without ever being fully explored. These megadungeons enabled Dave and Gary to run campaigns for dozens of players. On any day, they could host games for whoever happened to show up for a session. (See When Megadungeons Ruled Dungeons & Dragons.)

Even though the megadungeons under Greyhawk and Blackmoor became the foundation of Dungeons & Dragons, such dungeons rarely see play anymore. Why not?

1. Players never saw any examples. Originally, Gary thought that players would never pay for published dungeons. After all, players could easily make up their own. Despite this belief, TSR distributed the first published dungeon, Palace of the Vampire Queen. Strong sales proved Gary wrong, and so he set to publish his own dungeons. (See 9 facts about D&D’s first standalone adventure, Palace of the Vampire Queen.)

But Gary’s megadungeon under Greyhawk Castle seemed impossible to capture in writing. As adventurers explored and plundered, the dungeon changed constantly. New monsters wandered in to take empty rooms. Whenever the players’ attention turned, the layouts of old levels subtly changed. Entire new levels appeared. Most of the content lay in one-line descriptions, or worse, locked in the heads of Gary Gygax and co-dungeon master Rob Kuntz. Decades later, Gary wrote, “If we handed over the binders containing the maps and the notes, I don’t think even the ablest of DMs would feel empowered to direct adventures using the materials.”

So rather than attempting to capture Greyhawk Castle, Gary opted to publish adventures that he had created for D&D tournaments at conventions. For instance, the official D&D tournament at Origins ’78 ran the G1-3 adventures. The choice to publish such adventures changed the development of the game. D&D players everywhere saw Gary’s published adventures as a model. Instead of patterning their games after a megadungeon like the one Gary played at home, players imitated adventures created for a few hours of competition.

In 1990, TSR finally published WGR1 Greyhawk Ruins, its first megadungeon in print. “There are more than two dozen levels of horror and treasures. Run into brutal foes and gain uncountable wealth-nearly 1,000 separate room descriptions in all!” Gary had left TSR five years earlier, so fans hoping to explore his actual creation felt disappointed. James M. Ward and other veterans of the Grayhawk campaign still at TSR gave insights, but the dungeon even lacked the Great Stone Face Enigma of Grayhawk that Gary himself drew for the first D&D supplement.

The Ruins of Undermountain followed 7 months later. Undermountain appeared in a box with maps and with booklets that sketched out encounter areas. This outline mirrored the terse descriptions and evolving notes that Gary Gygax used for Greyhawk Castle, but the sketch failed to satisfy DMs accustomed to publications ready for play.

Perhaps locking a megadungeon in a book kills it. Printed pages cannot capture the dynamic essence of those original levels.

2. The ecology and rational of megadungeons seemed ridiculous. From they start, players struggled with the logic of megadungeons. Where did all those monsters get their food or leave their waste? Where did the creatures and treasure come from? Every dungeon master invented an insane wizard as an architect for their game’s underground sprawl until the notion became trite.

In the little, brown books, Gary suggested dungeons with layouts that always changed and grew to “maintain freshness,” but that made the megadungeon even more implausible.

Then Gary published adventures that featured a logic sometimes called Gygaxian naturalism. Monsters had lives of their own that involved feasting, scheming, sleeping, and everything but waiting for heroes to come kill them. Rather than wandering monsters living in defiance of reason, we saw giants and drow in their steadings and vaults. For many players, the giant- and drow-series adventures set an example that killed the megadungeon.

Soon, any DM peddling a megadungeon had some explaining to do. For instance, The Ruins of Undermountain kept to the insane wizard trope, then added magic that continuously gated in fresh monsters from across the Realms, and deep entrances that allowed creatures from the Underdark to well up.

3. Play styles expanded. Sometime in the middle of the 70s, for the first time ever, a party of adventurers visiting the inn met a hooded stranger with a job that needed doing. D&D expanded beyond a series of dungeon expeditions aimed at claiming treasure. Players began to favor games that mixed action with story. Waterdeep: Dungeon of the Mad Mage rates as my favorite megadungeon in print, but when I ran it, the group longed for a story and for motivations beyond a hunger for treasure.

4. Megadungons can feel monotonous. Even the biggest megadungeon only shows a tiny corner of the giant canvas that D&D worlds can offer. In a campaign limited to a single dungeon, kicking in endless doors to fight and loot can start fresh and thrilling but often becomes a tiresome slog. Even those of us who like dungeon crawls want to see some daylight and a plot.

5. Computers do megadungeons better. In 1979, computer games like Akalabeth and Temple of Apshai took gamers into megadungeons and started an electronic-gaming genre. Dungeon crawls limit players’ options, so they offer an easy premise for a computer game. (See How the Dungeon Powered the Success of D&D and the First Role-Playing Games.) With a computer DM, players can explore anytime. Digital dungeons offer faster play and better graphics. For players who just want to visit a sprawling underworld to kill monsters and take their stuff, electronic games probably offer a better experience.

Can a megadungeon work today?

A clever design can avoid the problems that pushed megadungeons out of play.

A story-centered game can take PCs into a megadungeon to accomplish more than looting. For instance, when Monte Cook created his superdungeon The Banewarrens, he paired it with overarching plot. Players don’t raid the Banewarrens just to loot. Instead, the story leads to objectives that require missions into the place.

Many megadungeons avoid monotony by introducing levels or zones centered on unique themes such as crypts, flooded sections, or fungus gardens. Even the levels under Castle Greyhawk followed themes that grew more exotic at deeper levels.

A megadungeon design can add intrigue and roleplaying by borrowing a page from The Keep on the Borderlands and adding factions of monsters. Players can join a side or play one against another. Factions under attack will bring reinforcements, creating more interesting battles, and giving players a reason for caution. The stories “Red Nails” by Robert E. Howard and “The Lords of Quarmall” by Fritz Leiber helped inspire the concept of dungeon exploring. Both yarns centered on feuds and intrigue.

A megadungeon (and a live DM) can create player agency and tests of ingenuity that no computer can match.

Although good design can yield a megadungeon that proves fun to play, ordinary dungeons can bring the same advantages. Today’s gamers tend to create megadungeons to foster nostalgia or to enable episodic play.