National Museum

The exterior of the National Museum may not be the most inspirational, but there's plenty to make up for that within. Here you'll find everything from Ancient Egyptian scrolls to ornate European furniture from the Renaissance. Naturally there are plenty of Polish gems, whether it be eighteenth century aristos outfits, or art-deco furniture. The gallery also has an extensive collection of Polish painting. The most fruitful era was c. 1850-1930, with stars such as Michalowski, Wyspianski, Podkowinski and Witkacy. Well worth investigating.

Good museum and good display of medieval armor inside and tanks and guns and planes outside. Good paintings inside.

I absolutely love this museum for all the Polish paintings on the top floors. Paintings of Polish hunting scenes, of snow, of sledges, hunting dogs, horses and giant pictures depicting historic battles.
There are paintings from the communist period, including my favourite "Thanking the tractor driver" and other paintings celebrating a worker in a fish factory who was the most productive at gutting the fish in the factory.
I will go there many times more.
There is also an excellent outside display of communist period tanks, aircraft and artillery that you can walk around.

quite big and impressing but not as good as warsaw rising museum