"World War I (1914-1918) involved more countries and caused greater destruction than any other war except World War II (1939-1945). An assassin's bullets set off the war, and a system of military alliances (agreements) plunged the main European powers into the fight. The war lasted four years and took the lives of about 9 million troops and more than 6 million civilians...(Read More)
Source Citation: Strachan, Hew. "World War I." World Book Advanced. World Book, 2010. Web. 4 Oct. 2010