Alongside "Come and See", Richardson's "The Charge of the Light Brigade", "Japan's Longest Day", and "The Big Red One", this would be on my shortlist for the greatest war film of all time.
Bears some similarities to Kubrick's "Paths of Glory", but Rosi's film (and I don't say this lightly) is much better. Rosi casts light both on universal military fault-lines and an intrigingly lesser known theatre of WWI, the Italian Alps in 1916.
There are several unforgettable scenes, including one where troops in plate armour attempt to storm the Austro-Hungarian positions. They look like Tin Man from "The Wizard of Oz", but the Italians did actually experiment with this "Farina" body armour.
Piero Piccioni provides an appropriately doom-laden score, and Rosi gets committed performances from his international cast of actors. One imagines that Gian Maria Volonte was particularly chuffed with the awakening Marxism of his character!
Now where are the remastered versions of Rosi's great trilogy from the 1970s? "The Mattei Affair", "Lucky Luciano", and "Illustrious Corpses". Criterion box-set please!