Allright, I admit, the last campaign I ran in Zama were plot-based, rather than sand-box based, campaigns. It was, in fact, a modified version (heavily modified) of EN's wonderful War of the Burning Sky campaign. At other times in the development of the campaign world, there have been dungeons that have (barely) qualified for mega-dungeon status, but usually too far away from the central geographic location of the campaign setting (the city of Zama, for which the setting is named) to be regularly visited by beginning characters.
The closest thing to an accessible dungeon the players had were the tunnels that run under the city, through the rock of the promonatory upon which the city sits. Being as they are a fairly advanced classical society, these tunnels include sewer systems, fresh water aqauducts and cisterns (all maintained by the "Grey Men" of the undercity. Something of a mystery cult dedicated to preserving the life's blood of the city. That is, it's water supply and who regard the city itself as a living being).
Beyond these (or rather, deeper down the rock face) were older caverns, seige stores and tunnels leading down to the military harbour carved from the base of the cliff by the hand of a sea-titan in return for the hand of a Zaman princess. Although most of these areas were patrolled, there were a few disused areas inhabited by runaway slaves and their descendants, plus the odd slime, ooze and a few powerful tribes of were-rats and smugglers. All in all, a nice enough adventure location within the city, but not really a fully fleshed mega-dungeon as such. Mostly because there was too much "official" traffic to really justify populating the place with as many monsters as I would like.
Now though, while I'm in the process of re-imagining the campaign setting (yet again), I really should be thinking about opportunities to place a mega-dungeon setting closer to home. So far I've come up with three alternatives:
- Taking the Caverns of Thyatis and fleshing them out into a proper, full-sized megadungeon and city ruin, while keeping much of the backstory. In this particular case, the city would either be located in the interior desert close to Numidian territory (in which case it would be an ancient Kushan city and the Death God referred to would be the Serpent God of Kush) or else make it the ruins of a city once peopled by the original inhabitants of the Balaerian Isles. Admittedly, thats two sepeate alternatives in one bullet point, but there we go. It's not like I'm writing a powerpoint presentation here is it?
- The usual stalwart of an ancient dwarf or elf (Shee or Unshee) city recently re-discovered somewhere in the mountains north of the Citadel of Gates. If I chose this thoroughly unimaginative option I'd probably use the thoroughly well-imagined Stonehell dungeon as a starting point, though that would hardly count as adding my "own" megadungeon to the setting, now would it?
That should buy me plenty of time to think about expanding old Thayatis into a proper mega-dungeon, properly adapted for play in the Zama setting.