Oh! What a Lovely War, an extraordinary movie from 1969 that records the first world war as a musical using actual songs from the period and real historical speeches and documents, intercutting fantasy scenes on the (now destroyed 
) West Pier at Brighton with “realistic” battle footage, is just recently available on DVD ($13 at Amazon). This is a flawed masterpiece, with emphasis on the latter; an all-star production (both ways: most of the many important parts are played by stars, and most of the stars of British cinema appear to be in the cast) , a powerful and bitter anti-war message with Brechtian irony and humor, echoes of lots of other historic movies (for example, Olivier’s Henry V, with its cutting from stage to realism). It’s notable for registering the real horror of violent death (cf. M and its famous rolling ball scene) without showing it at all, triggering our own imagination by the occasional appearance on screen of blood-red poppies.
And of course bitterly relevant today, even if what we’re embroiled in in Iraq can no longer be called a war.
