As you need to improve your film culture, here you have some very good films about World War 1. I'm including a short explanation of the plot in order to pique your curiosity ;)
ALL QUIET ON THE WESTERN FRONT (1930)
This is an American film that tells the story of German soldiers on the Western front and how their opinion about war transforms from patriotism to disillusionment. The film was forbidden in several countries due to its anti-war content.
LA GRANDE ILLUSION (1937)
This is a French film that tells the story of two French war prisoners who try to escape from several Prisoners of War camps. During their confinement, they meet some Germans and receive news from the Battle of Verdun. This film was forbidden by the Nazis and also in France during World War 2.
THE AFRICAN QUEEN (1951)
This film happens in Eastern Africa and tells the story of a Canadian boat captain and a missionary woman who try to make war against the Germans on their own and attack a German warship. This film is a comedy with Humphrey Bogart and Katharine Hepburn in the leading roles.
PATHS OF GLORY (1957)
This film was directed by Stanley Kubrick and is one of the best anti-war films in history. It tells the story of the soldiers' mutinies in the Western Front and the officers' cowardice and ambition. This film was forbidden in Spain during Franco's dictatorship and wasn't shown in cinemas until 1986.
LAWRENCE OF ARABIA (1962)
This film tells the story of T. H. Lawrence, a British officer who had an important role in the allied victory against the Ottoman Turks. He convinced the Arab tribes to revolt against the Ottoman Turks, but his promises of self-determination were not included in the peace plans of the winners.
JOHNNY GOT HIS GUN (1971)
This film tells about the dramatic consequences of the war. It was written and filmed by Dalton Trumbo, who was very shocked when he met a soldier disfigured during WW1. The hero of the film is a quadruple amputee, who lost his eyes, ears, mouth and nose on the front, buy is still able to think. He remembers his life and thinks about what he can expect in his situation.
This film tells the experience of the Australian soldiers in the battle of Gallipoli, one of the biggest disasters of the British army during WW1.
LIFE AND NOTHING BUT (1989)
This French film by Bertrand Tavernier tells the story of a French officer in charge of identifying unknown dead soldiers at the end of the war.
CAPTAIN CONAN (1996)
This one is another French film by Bertrand Tavernier about what war makes with men. Captain Conan is a French officer used to kill who has to adapt to the end of the war when his troops are in Romania.
A VERY LONG ENGAGEMENT (2004)
This film tells about five French soldiers accused of desertion from the trenches of the Somme. One of the soldiers' girlfriend doesn't believe the official version of their disappearance and tries to find him. The recreation of the trenches and the war front is extraordinary.
I liked all these films. Watch them if you have the chance. Some of them are frequently broadcasted on the TV.