My favorite kind of museum are militiary history museums. Much of the technology we take for granted today was created for use in war. You can study the evolution of weapons, uniforms, communication technology, medical sciences, engineering, aviation and transportation. Museums I highly recommend people to visit and are no particular order.
Virginia War Museum, Newport News, VA.
National Museum of the Marine Corps, Triangle, VA.
Australian War Museum, Melbourne, Australia
Imperial War Museum, Lambeth, London, England
Royal Army Museum, Chelsea, London, England
Airborne Museum, Hotel Hartensein, Oosterbeek, Holland
National Military Park, National Park Service, Gettysburg, PA
Army Heritage Center, U.S. Army War College, Carlisle, PA
Musee L'Army, Invalides, Paris, France
D-Day Museum, Bayeux, Normandy, France
Musee L'Army, Brussels, Belgium
82nd Airborne Museum, Ft. Bragg, North Carolina
Airborne and Special Operations Museum, Fayettville, N.C.
Infantry Museum, Ft. Benning, Georgia.
Canadian Forces Museum, Ottowa, Canada.
This is just a partial listing of some of the world's great museums.