The National Postal Museum is part of the Smithsonian Museum. It is an enormous building, filled with all sorts of things related to the mail. There was no way to get through it in my sub-60 minute time slot. I made the best of it. Visitors can take up to 6 stamps for their own collection.
Here are my picks.
Also, I found queen bees there. Unique mailing packages were featured in one exhibit, including a queen cage. The interpretive sign read, “In the 1890s, beekeepers shipped queen bees through the mail in containers like this. Bees and a variety of insects can still travel through the mails today.”
There was also an exhibit about Alexander Hamilton. I’m not entirely sure what the postal connection was — I entered the side rather than the front of this room. Below are guns from that exhibit, unsure who owned/used them or if they were involved in a duel. I didn’t take time to read because there was another visitor who definitely was reading the display and I wasn’t going to wait. And there was a guard. But they seemed special so I photographed them. The other visitor was nice to back up enough for me to snap this: