South Dakota Air and Space Museum

Free admission is not a neutral fact here — it's a policy that says something. The South Dakota Air and Space Museum, managed by the 28th Bomb Wing on the grounds of Ellsworth Air Force Base outside Box Elder, holds more than 30 aircraft, helicopters, and missiles in its outdoor airpark, along with indoor galleries covering a century of military and civilian aerospace. The building itself was once operational: the hangars housed fighters sitting alert against Soviet bombers during the Cold War. That history is the exhibit.