This is hardly a new revelation I'm sure, but realizing that Tolkien's elvish architecture (as designed by John Howe and Alan Lee) was inspired by art nouveau, and the dwarves' architecture was inspired by art deco, made me geek out because it's so clever
Doubtless there are other posts about this but I'll explain for anybody who doesn't know about this because I'm so happy about it:
Art Nouveau is inspired by organic shapes and the natural world. It emerged also from the Arts and Crafts movement, which was a response pushing back against industrialization.
Makes sense for elves because of their relationship to nature and how old they are, right?
Dwarves, on the other hand--their motifs are inspired by art deco. Art deco, in turn, was the replacement for art nouveau, embracing technology and industry and focusing on geometric shapes.
Example from the Hobbit movies:
It works so well because dwarves have such a heavy focus on industry and technology from their very creation by Aulë, and also their history--sleeping until after the elves were made. I'm just screaming over how smart it was to pull artistic inspiration from these two movements!! Like from a design standpoint they work so well, but they also mirror both the culture and history of these civs and I just think that's so neat!!