research i had done previously actually really was applicable most of all, the research that i did on olmstead which involved trying to learn about and describe landscapes. the landscapes he was creating were for pleasure, for recreation, but there are certainly thoughtful landscapes in which the features of the landscape really came into play. if there's a beautiful bridge, it's where it is for a reason. if there's a meadow, it is where it is for a reason. antietam i found -- i was amazed when i started working on it -- i should mention by the way, about a thousand acres, antietam is 3,000 acres. they are similar in size. and what really amazed me was although it wasn't by any kind of intent, all of the features, the sunken road, antietam creek, the burnside bridge, they all came into play, and so the need to describe this landscape and how it was navigated by the men on the field that day, you know, it made it the fact that i had some grounding writing about landscape architecture actually came in handy to work on a book on antietam. >> uh-huh. >> thank you very much, everybody. [applause]