World War I was different from other wars because of the use of advanced industrial technology and weapons and because of the unprecedented number of countries that took part. Unlike previous wars, a large portion of the civilian population mobilized for World War I.
World War I was the first war where aviation was used by several of the participating countries, including the United States, Britain and France. The number of casualties was unprecedented, with millions of people losing their lives on the Western Front alone. The political alliances between the major powers and the length of the war were also without precedent.