Imagine a world that for some reason undergoes a period of rapid cooling, causing an abrupt (over like 300 years) drop in sea levels.
Image an area in such a world that is populated by a lot of islands and a relatively shallow (100 meter) continental shelf - and all of a sudden, that continental shelf becomes land. We're also going to assume (because obviously we're not limited to Earth lifeforms) there's some fungal-like organism that has evolved to incorporate salt into its structure. Once this land is exposed, those organisms rapidly spread throughout the salt plane areas near the island, storing the salt in its mass as massive natural columns that, when gone, allow plant life to grow there as tidal pools left behind are desalinated by these fungal lifeforms.
Imagine what civilization would look like there. You have a region where there are cities and civilizations on the islands that dot the landscape on what look like massive plateaus, and around these islands are wide fields of new growth, interrupted by columns of salt several dozen meters tall, which are sometimes part of the same culture as the island overhead but other times movement between the two areas is so difficult that they've culturally diverged. Then between those islands you still have vast salt flats, the edges of which contain the mushrooms that made this place habitable, a barrier that was almost impossible to cross in any real numbers just from how arid it was, but recent developments have finally made trade between these salt islands possible.
I just feel like it would be neat to play with.
