The first world war was fought in the early 20th century. This conflict broke out over the European continent and was abbreviated WWI. The war began on 28 July 1914 and ended on 11 November 1918. World War I killed millions of people in a number of countries, including the United States, Russia, and Germany. The earliest known survivors are listed below. There were no winners in this war, and the conflict was ultimately lost due to a lack of funding.

In the summer of 1915, Britain and France attacked the Ottomans in the Middle East and Egypt. In early 1916, the British retreated from Gallipoli. In addition, the British and French forces fought Ottoman Turks in Egypt and Mesopotamia. In northern Italy, Italian and Austrian forces fought 12 battles along the Isonzo River. The First Battle of the Isonzo took place in late spring 1915, shortly after Italy entered the war. Later that year, the Twelfth Battle of the Isonzo, also known as the Battle of Caporetto, was won by Austria-Hungary.

On 4 October 1918, Germany requested an armistice. It claimed that this deal was designed to kill twenty million Germans. Its people suffered greatly from food shortages and inflation. The treaty ended in 1919 with the signing of the Treaty of Versailles, which imposed a series of peace treaties on the Central Powers. It also created the League of Nations and allocated territory to the victors. The resulting treaties brought bitterness to Europe. Austria-Hungary was divided into several successor states, while the Russian Empire lost most of its western frontier.