AP
An US soldier in the First Division throwing a hand grenade in France on March 15, 1918.
World War I, which ended 99 years ago on Saturday, took the lives of about 40 million people and is considered by many to be the first total, industrial war.
Although World War I did not deliver on its promise to be the "war to end all wars," its conclusion on November 11, 1918, has been celebrated around the globe as Armistice Day. In the US, it is marked as Veterans Day.
Here are 15 striking photos from the war to commemorate veterans in the US and around the world: