Probably the city of Saints and Madmen by Jeff Vandermeer. The later two books in the ambergris Trilogy don't feel quite as fantasy, so I'm not sure they would count for this. I don't read that much fantasy anymore? Most of my taste is modern weird or sci-fi these days.

Allow me to ask the follow-up question of your favorite sci-fi novel.      _{Optional: motivate your answer. Give me a cool review!}