World War I: In "the day Sussex died", elements of the Royal Sussex Regiment take heavy casualties in the Battle of the Boar's Head at Richebourg-l'Avoué in France.

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,…