While everyone obsesses over Ottoman architecture, Karaköy has stunning Art Deco from when it was the financial district. The Minerva Han and Harikzedeler Apartment show geometric facades with period metalwork.

Walk Voyvoda Caddesi and look UP - most people just focus on trendy cafés at street level. Curved corner windows, terra cotta details, stylized ornaments influenced by New York and Paris examples.

Built during 1920s-30s rapid modernization. Much more interesting than taking the same Blue Mosque photos as everyone else.