Invisible Cities: Argia Building Shape Ideas

So here are three really basic building shape ideas for Argia inspired by stalagmite/stalactite structures in caves. I'm going to make at least one of them more detailed so I can see what I can do to the actual architecture to make it more interesting. I've been looking at Notre Dame, Pére Lachaise Cemetery, and Sagrada Família. I've also been looking at some architecture from Lord of The Rings and a few other films but I'm trying to stick to real life examples for the actual structure at least. The real challenge is to make sure this city stays eerie/menacing. I'm also not 100% sure of the colour scheme still but I figured this was more interesting than keeping it black and white.