If you’re visiting Washington D.C., odds are you will visit at least one of the 21 Smithsonian museums during your trip. We were able to see the National Air & Space Museum, the Museum of Natural History and the Museum of American History on our recent trip. Follow along for tips and information about these amazing places. Some links may be affiliate links. By clicking on them I may make a small commission at NO extra cost to you! What to Know Before you Go Security Just like most tourist spots in Washington D.C., you will need to go through airport-style security to enter a lot of the Smithsonians. While…