Smithsonian National Air and Space Museum.
As you can see, there was a lot to take in. I really liked the fact that we were allowed to take pictures of anything, and most displays we were able to walk up to and touch if we wanted. If a display was to be protected, it was generally behind glass, so there was no confusion.
I could have easily spent a day or two here, and probably will return, given that Holly's family is not far away.