Serbia Declares War on Turkey
Theatre definitions: Western Front comprises the Franco-German-Belgian front and any military action in Great Britain, Switzerland, Scandinavia and Holland.
Eastern Front comprises the German-Russian, Austro-Russian and Austro-Romanian fronts. Southern Front comprises the Austro-Italian and Balkan (including Bulgaro-Romanian) fronts, and Dardanelles. Asiatic and Egyptian Theatres comprises Egypt, Tripoli, the Sudan, Asia Minor (including Transcaucasia), Arabia, Mesopotamia, Syria, Persia, Afghanistan, Turkestan, China, India, etc. Naval and Overseas Operations comprises operations on the seas (except where carried out in combination with troops on land) and in Colonial and Overseas theatres, America, etc. Political, etc. comprises political and internal events in all countries, including Notes, speeches, diplomatic, financial, economic and domestic matters. Source: Chronology of the War (1914-18, London; copyright expired)
World War I (abbreviated as WW-I, WWI, or WW1), also known as the First World War, the Great War, the World War (prior to the outbreak of the Second World War), and the War to End All Wars, was a global military conflict which involved most of the world's great powers, assembled in two opposing alliances: the Allies of World War I centred around the Triple Entente and the Central Powers, centred around the Triple Alliance. More than 70 million military personnel, including 60 million Europeans, were mobilized in one of the largest wars in history. More than 15 million people were killed, making it one of the deadliest conflicts in history.
Wikipedia: World War I
First World War.com