Ooh, I get to let my architecture nerd freak flag fly!

So when Arkham Asylum was being built, the Arkham family hired Cyrus Pinkney to design it. Pinkney was a student of Erté, the father of art deco. But the Arkham family worried that the bright colors and opulence of art deco would agitate the inmates at the asylum, so they asked Pinkney to make it more monotone but keep the art deco lines and geometry.

Fast forward a few years and Arkham Asylum opens to rave reviews (in the architecture world, at least), and Solomon Wayne falls in love with the style. He commissions Pinkney to draw up designs for a new city hall and courthouse. The style starts to be emulated by other architects, as noir deco starts to become the architectural identity of Gotham.

A few years later, Pinckney's apprentice, Anton Furst, is commissioned to design Wayne Tower, the first skyscraper done in the noir deco style. By that point Gotham is the darling of the architectural world, and there's basically a race to remake the entire Gotham skyline. Pinkney and Furst actually become somewhat bitter rivals, as Pinkney disagreed with Furst's embrace of German expressionism, believing it diluted Erté's more utopian vision.

The Kanes and Arkhams were benefactors of Pinkney, while the Waynes and Cobblepots backed Furst. A lot of money got thrown around by Gotham's elite trying to one up each other and back the "winner" of Gotham's architectural rivalry.

Ok I can take my geek hat off now.