World War I

World War I
World War I (WWI), which was predominantly called the World War or the Great War from its occurrence until 1939 (World War II), and the First World War or World War I thereafter, was amajor war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918. It involved all the world's great powers, which were assembled in two opposing alliances: the Allies (based onthe Triple Entente of the United Kingdom, France and Russia) and the Central Powers (originally centred around the Triple Alliance of Germany, Austria-Hungary and Italy; but, as Austria–Hungary hadtaken the offensive against the agreement, Italy did not enter into the war). These alliances both reorganised (Italy fought for the Allies), and expanded as more nations entered the war. Ultimatelymore than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history. More than 9 million combatants were killed, largely because of enormousincreases in lethality of weapons, thanks to new technology, without corresponding improvements in protection or mobility. It was the sixth-deadliest conflict in world history, subsequently paving the wayfor various political changes such as revolutions in the nations involved.
Long-term causes of the war included the imperialistic foreign policies of the great powers of Europe, including theGerman Empire, the Austro-Hungarian Empire, the Ottoman Empire, the Russian Empire, the British Empire, the French Republic, and Italy. The assassination on 28 June 1914 of Archduke Franz Ferdinand ofAustria, the heir to the throne of Austria-Hungary, by a Yugoslav nationalist in Sarajevo, Bosnia and Herzegovina was the proximate trigger of the war. It resulted in a Habsburg ultimatum against theKingdom of Serbia. Several alliances formed over the previous decades were invoked, so within weeks the major powers were at war; via their colonies, the conflict soon spread around the world.
On 28...