I watched this documentary recently. Pretty interesting. It gives a useful brief summary of the causes of the war and then moves on to the personal stories of individuals who fought in it. From the YouTube description:
“World War I: American Legacy” vividly tells the many forgotten stories of the men and women who served in the Great War, reminding Americans of their impact on our country that can still be felt today. Narrated by David Carradine.
From the summer of 1914 to November 1918, the Great War cost over 14 million lives, devastated entire countries and destroyed countless architectural landmarks. The war also led to important developments in literature, technology, music and social equality that have shaped the culture of 21st century America. Monuments and dedications to World War I veterans surround Americans today as a tribute to their service and sacrifice.
Charles Whittlesey of the Lost Battalion and Father Duffy of the Fighting 69th became famous for surviving against impossible odds. Pilots Victor Chapman and Quentin Roosevelt and ambulance drivers like Richard Hall made the supreme sacrifice.