If you make your way to Finland, the PAROLA TANK MUSEUM is a "must visit". Its about 2 hours north of Helsinki and has about 60 tanks (mainly WWII-era) and about the same number of artillery pieces. Also has an armored train. Most of the WWII tanks are rare (especially from a North American point of view). The aviation museum near Vantaa airport (forget its name) is also worthwhile. While not nearly the same size as the USAF Museum in Dayton, they do have a few interesting things. The Anti-Aircraft Museum is also close by, and it also has a lot of unique WW2 equipment (mainly machine guns and small AA guns) in addition to a lot of Cold War-era SAMs. As for North America: -USS Slater in Albany, NY (last Destroyer Escort of its class afloat) -USS Intrepid in NYC. This is getting really overcrowded, but it is worthwhile to see if you're in NYC. -Battleship Cove in Fall River, Massachusetts (home to the BB USS Massachusetts, a DD, PT boats, East German frigate and the USS Lion-fish submarine) -the USAF Museum in Dayton, Ohio (This is probably the top attraction for me) -Pima Air and Space Museum in Tucson, AZ. This is on the same scale as the USAF Museum, but the planes are mainly outside. Bring a water bottle, as there is lots of walking! The aircraft "boneyard" is across the road, and you can buy tickets for a tour if you want to view it -Canadian Warplane Heritage Museum in Hamilton, ON. This is really close to me, and they do have some interesting things (although it is small compared to the previous two) -HMCS Haida in Hamilton, ON. Again, a small museum consisting of the destroyer HMCS Haida. Worthwhile to visit if you are in the area. As a side note, if you are in the Tucson area, the Titan Missile Museum about an hour south of the city on the I-10 is worth your time. Not WWII-related, but interesting to see.