Writers: have you written a story that took a TON of research?

The first novel I worked on was set from about 1184-1195 and in England and Outremer (The Holy land) so I basically read anything I could on that time, and the history behind the Crusades. I enjoy research, especially historical research, although (from choice) I only write fanfiction set in Tolkien's universe now, I have in a sense researched his many works, including those posthumously published by his son, over 20 years. Thorough research, in any story, even something as simple as the climate and wildlife of a certain place, gives a much deeper sense of reality to a novel.