World War I was a global conflict that left unprecedented destruction and death, with millions of people killed. Its belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire. Fighting took place across Europe, the Middle East, Africa, and parts of Asia. New technology, including the recent invention of the airplane, trench warfare, and especially chemical weapons made it one of the deadliest conflicts in history. An estimated 9 million soldiers died in combat, with another 5 million civilian deaths as a result of military actions, hunger, and disease. Millions more died in genocides within the Ottoman Empire and the 1918 influenza pandemic, which was exacerbated by the movement of combatants during the war.