The Holocaust Museum is amazing. Any of the memorials. I'm from IL and enjoy the Lincoln. Viet Nam wall is great. I lucked out with one of those visiting WWII vets flights at the WWII Memorial when I was there, complete with a full-dress Marine playing Taps and current soldiers escorting the vets and a flag ceremony for each service. I went around thanking all for their service. I was in tears. That group was from Chicago; if my Dad had still been alive, he'd have been there. A tour of the memorials and area at night is a beautiful perspective. Once with a group of women, we left the group taking a tour bus and struck our own deal with one of the private tour guides to take us around. He knew things we didn't know about, took us where ever we asked, and knew people to sneak us into tours that were booked up. I agree with all the above ideas. Oh, and go by the IRS !!