1917 is one of the best war movies I've ever seen. Below is the synopsis:
"During World War I, two British soldiers -- Lance Cpl. Schofield and Lance Cpl. Blake -- receive seemingly impossible orders. In a race against time, they must cross over into enemy territory to deliver a message that could potentially save 1,600 of their fellow comrades -- including Blake's own brother."

I liked it because it's aimed to show how the soldiers really had it in the middle of the war. It's not a national's propaganda about how the mighty super-countries won the war. It's from the soldier's perspective.