What are some good nonfiction books that are advanced? ?

I have homework to do over the summer for my AP English class and we have to read a nonfiction book of our choice. I was thinking something along the lines of the Holocaust or World War II maybe, but other than that I have no idea. I'm leaving to go to Barnes & Noble in about a half hour so if you have any book suggestions, PLEASE leave a comment; it is greatly appreciated. Thanks!