'The Big Parade'

Utterly shocked to see how King Vidor portrayed war in this film. Especially for the time (released in 1925 .. seven years after World War I ended), that big battle scene is as terrifying as you'll find on the big screen.

Outside of the first five minutes of Steven Spielberg's Saving Private Ryan I don't remember a better full-on battle scene and a more realistic vision of war. As it should be.