Io accuso (1938)

After serving in the trenches of World War I, Jean Diaz recoils with such horror that he renounces love and personal pleasure to immerse himself in scientific research, seeking a machine to prevent war. He thinks he has succeeded, but the government subverts his discovery, and Europe slides with seeming inevitability toward World War II. In desperation, Diaz summons the ghosts of the war dead from the graves and fields of France to give silent, accusing protest.