World War or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a global conflict between two coalitions: the Allies (or Entente) and the Central Powers. Fighting took place mainly in Europe and the Middle East, as well as in parts of Africa and the Asia-Pacific, and in Europe was characterised by trench warfare; the widespread use of artillery, machine guns, and chemical weapons (gas); and the introductions of tanks and aircraft. World War I was one of the deadliest conflicts in history, resulting in an estimated 10 million military dead and more than 20 million wounded, plus some 10 million civilian dead from causes including genocide. The movement of large numbers of people was a major factor in the deadly Spanish flu pandemic.