So, in 1986 I sold my first manuscript to Scholastic- a book called "The Moonclock". The story is set during a pivotal moment Vienna, about 1683 or so, a big pillow fight involving the Turkish army taking a thumping from a little girl named Robin. Any way, that's not the important part. The important part was my little fallacy that somehow, if I promised to go to Vienna and do research, Scholastic would get all excited and give me a bigger advance. They didn't. I went anyway. Here is a page from this enormous sketchbook I dragged along with me- thing's gotta be about 6 feet by 8 feet. Okay, that's an exaggeration. But it felt that big. I think maybe it's 16 inches by 20 inches. These thumbnails were done at the Museum of Military History, or, as the Viennese would call it- Heeresgeschichtliches Museum Wien. They had tons of stuff left behind by the Turks after they got trounced- tents, armor, swords, camp chairs, pillows, cell phones- all sorts of stuff.
I coulda spent months in there.