King Vidor's "The Big Parade" is the biggest blockbuster from the silent era, and became the gold standard to which all others were compared well into the 1930s.
The story focuses on three American doughboys, fighting in Europe during WWI. Two are working class; a tobacco spitting riveter, Slim, a barkeep, Bull, and a ne'er-do-well son of wealth, Jim, who was shamed into enlisting by his family. These three go through the hardships of military training together, bond, and become fast friends. Their friendships deepen after they are shipped to France where Jim falls in love with a French farm girl. This comprises the first half of the 2 1/2 hour movie. The second half of the movie is the gritty reality of trench warfare.
Some say that this is one of the first big-budget anti-war movies. I'd take issue with that, but the film does show the human cost of war without condemning it outright. Remember that WWI was 'the war to end all wars', and in 1925 this was still a possibility. But "The Big Parade" does take an unflinching look at the affect of war on both combatants and non-combatants.
The performances and direction are excellent and silent or not, this is a movie well worth seeing.