It was a global conflict originating in Europe that lasted from 28 July 1914 to 11 November 1918. It led to the mobilisation of more than 70 million military personnel, including 60 million Europeans, making it one of the largest wars in history. An estimated nine million combatants and seven million civilians died as a direct result of the war, and it also contributed to later genocides and the 1918 influenza pandemic, which caused between 50 and 100 million deaths worldwide. Military losses were aggravated by new technological and industrial developments and the tactical stalemate caused by gruelling trench warfare. It was one of the deadliest conflicts in history and precipitated major political changes, including the Revolutions of 1917–1923, in many of the nations involved. Unresolved rivalries at the end of the conflict contributed to the start of World War II about twenty years later. [Wikipedia]