World War I: The American Expeditionary Forces begin to arrive in France. They will first enter combat in the Battle of Hamel on July 4.

World War I, or the First World War, also known as the Great War, was a global conflict between two coalitions: the Allies and the Central Powers. Major theatres of war included Europe and the Middle East, and well as parts of Africa and the Asia-Pacific. One of the deadliest conflicts in history,…