After looking over Neverwinter, thinking about my own 4E Phlan, and remembering some others from older editions and other games I realized that I am a huge fan of the rpg adventure set in the ruined city. For me the sense of mystery and wonder peaks with the exploration of the city in ruins, even more so than the typical dungeon or even megadungeon. Some of that probably ties into my affinity for post-apocalyptic settings where the lost ancient city looms large (like in Gamma World) and the prospect of a ruined city in a fantasy game pulls some of that PA element into it - I mean, SOMEBODY used to live there and if it's ruined now then they would probably describe it as post-apocalyptic from their viewpoint!
You don't get a ton of ruined cities in some of the classic sources - LOTR has Osgiliath, I suppose, and maybe Minas Ithil, and fairly tales and mythology don't usually get into things like that but pulp and sword and sorcery... now we have some material. The search for the lost city is a common theme in these works, from about every third Conan story to IMO the best Cthulu story - At the Mountains of Madness which is set in an ancient ruined city. Movies and TV shows tap into this sometimes too, from Sinbad to Escape from New York to Indiana Jones. It's a rich trove to mine with lost secrets of magic or technology, ancient knowledge, and terrible guardians aplenty.
I might also argue that a ruined city makes more sense than the huge underground complex, at least I would think there would be many more ruined cities than complex excavations rivaling the NYC subway system. in a typical fantasy world. YMMV of course but it's easier to explain in many ways and a little more familiar to the modern player.
Ruined cities have been well-represented in fantasy RPG's but maybe not as much as big dungeons. Some high points for me:
- The first one I would nominate is I1 Dwellers of the Forbidden City, which while not extnesively detailing all of the ruins, did at least include a map of the whole ruined city. For being crammed into a small page count it does a pretty good job of setting things up.
- B4 The Lost City is an odd one as it is a city but it is also buried underground in a kind of arcology. I like it, so let's count it.
- Ruins of Adventure is in here of course as Phlan was covered in a pretty big softbound module.
So Basic and 1E were represented but 2E is a little dry. I suppose ROA was considered 2E as well so maybe it's one per edition of the game.
- 3E had The Lost City of Gaxmoor and The Lost City of Barakus from third party publishers, both of which were interesting
- Alongside 3E Monte Cook's Arcana Evolved had a really nice big adventure called Ruins of Intrigue which I really liked and would probably used if I started up a game of that - the only flavor of 3E I am interested in running at this point. There are various things living in the ruins and factions competing with each other as well in a real sandbox setting, not a linear story arc waiting to be acted out.
- Monte Cook also gave us Ptolus, the mega-supplement, and while not technically ruined it does sit atop a huge dungeon, next to a huge graveyard, and near an evil mage's fortress, so it's not in the best shape.
4E has had Vor Rukoth which I understand is sort of a ruined city in a small package and it now also has Neverwinter, the inspiration for this whole discussion.
Beyond D&D there was RQ's Big Rubble which I know little about but I do know it was a pretty popular setting for adventuring and was a ruined city.Warhammer had Mordheim which was a city flattened by a comet which left behind deposits of warpstone, a valuable magical resource that drew in adventurers from all over the world. I'm sure there were others too but I'm not remembering them as I write this.
There are several advantages to the ruined city as an adventuring environment. There is usually a small settlement of some kind or base area, and the areas near that tend to be the least dangerous, growing more and more dangerous as one ventures deeper into the ruins. This makes it easy to "zone" things so that players do not get in over their heads, but it also keeps the other areas "visible" to the players. You don't have to find the stairway down to dungeon level 9's Burial Pits - you can see the Haunted Graveyard from the window of your room at the inn! If you think you're tough enough you can go there right now! It sets things up for a true sandbox, where the players can go where they please and into as much danger as they can stand, without neccessarily having to pass through all of the prior material, unlike a conventional layered dungeon. You can have variety comparable to a wilderness area packed into ruined city, cutting down on travel times and ration checks and letting you get to he good parts thsat much faster.
So what can I say? I like the ruined city, probably more than I like even the megadungeon, though they are really not that far apart and each can take on aspects of the other. Both are usually landmarks in the world, both tend to have factions within and without, giving the PC's something to hook in to. Both tend to cover a fairly large area physically. Both tend to cover a range of adventuring difficulty as well, from starter to veteran. Also, if you do either of them right, they will become legends among your players, not just your campaign world.