One hundred years ago the guns fell silent – at least mostly. While it could have remained a regional spat in the Balkans following the assassination of the heir apparent of Austria-Hungary in Bosnia in June 1914 instead it boiled over into what would eventually be known as the First World War. Today it is remembered mostly for the trench warfare on the Western Front, but World War I was one of many covert operations, subterfuge and secret treaties.
Test your knowledge of the Secrets of the Great War:
