
Originally Posted by
LuckyFish
This got me thinking about all the areas that look like they should be a dungeon entrance but (at least as far as I know) aren't. Some of them might be used in solo content I haven't gotten to yet, but the one that springs to mind immediately is the tomb just outside Ul'dah with all the Spriggans. What is that place?
That's the Sil'dih Excavation Site - the ruins of Ul'dah's former twin city which was destroyed in a war years before. The exact details of what actually happened are murky at best, Ul'dahn history (which, as Ferne himself stated, is usually "written by the winners" and so might not be necessarily true from a certain point of view) states that the war was because of dwindling water supplies and which Sil'dih was losing horribly, which caused them to resort to no less than necromancy to revive their fallen soldiers as a zombie horde simply in an effort to recoup their mounting losses against Ul'dah's forces.
This apparently backfired on Sil'dih horribly though, in that the zombie plague used to revive their dead soldiers now spread from the military to the city itself and pretty soon the entire nation was wiped out both by the zombies and an empowered Ul'dah who now turned the war into a public relations stunt to "send these zombies straight back to Thal!" Prior to the Calamity, Sil'dih was entirely buried under the sand, occasionally being seen off on the horizon as a shimmering mirage, but the geographic upheavals to the land Dalamud's fall wrought revealed the ruins.
Of course, as noted the truth is far more murkier than that -
the Hildibrand quest line suggested that it was in fact Ul'dah which really unleashed the zombie apocalypse on Sil'dih - which drove that quest line's antagonist to get revenge on Ul'dah for the city's destruction. However, given the Hildibrand storyline exists in a kind of parodic 'bubble' that is not necessarily canon to the main scenario, it's unclear exactly if even that is truly what happened (I lack the lore book so I am unsure exactly if anything more or less than this is listed there on the subject). Either way, those ruins are of the former city of Sil'dih which was destroyed in a zombie apocalypse.
Incidentally, you actually travel through there during the ending cutscenes to the 2.55 storyline - the Sil'dih Aqueducts connected Ul'dah to it and the player's character exited the Aqueducts through there when fleeing from the Crystal Braves and the Brass Blades (an early Ul'dah main scenario quest instanced battle also takes place outside there too).
So the ruins of Sil'dih definitely appear in the game and are important to the game's storyline.