Vietnam Military History Museum is one of Hanoi's major history museums, with aircraft, tanks, artillery, and exhibits covering Vietnam's long military struggles. The outdoor hardware is striking, but the real value is how the museum frames the wars within Vietnamese national history.
It is a sober, sometimes one-sided, but important stop. Combine it with the nearby Flag Tower and other Ba Dinh-area sights, and allow time to read rather than only photograph the aircraft.