For anyone planning a visit to DC, an absolute must-see is the
International Spy Museum! What a way to spend a half-day!!!
It starts with a challenge to select a "cover" persona (from many posted in a room) to memorize, then see if you can recall the details of who you are supposed to be when questioned by authorities. There's fictional spy memorobilia, like a James Bond car from the movies. And there are tons of actual items used by spies over the years - ball point pen weapons and button cameras, information about bugging rooms and surveillance techniques. Computerized interactive displays challenge you to identify costumed spies from their natural photos or descriptions, while watching security camera footage. There's info and videos about spies from the world wars... and up through recent years... and famous celebrities and sport figures who accepted spy assignments from the gov't while they toured in other countries (or here, from other countries).
We've been to this museum on two different Washington DC visits. It was fascinating, both times! Highly recommended!