World War I, also known as the Great War, was a global conflict that lasted from 1914 to 1918. It involved the major powers of Europe and their colonies, as well as the United States and other countries from around the world. The war was fought primarily in Europe, but also in Africa, the Middle East, and Asia. It was one of the deadliest conflicts in human history, with an estimated 8.5 million soldiers and 6.5 million civilians losing their lives.

The causes of World War I were complex and varied, but the main trigger was the assassination of Archduke Franz Ferdinand of Austria-Hungary by a Serbian nationalist in June 1914. This event set off a chain reaction of alliances and DW News Today conflicts that eventually led to war. The major powers of Europe were divided into two opposing alliances: the Allies (France, Russia, and Great Britain) and the Central Powers (Germany, Austria-Hungary, and the Ottoman Empire).

The war began with a series of rapid military offensives, but soon turned into a stalemate as both sides dug in their trenches and fought a brutal war of attrition. New technologies such as machine guns, tanks, and poison gas made the war more deadly than ever before. The war also saw the first use of airplanes in combat, which would go on to become a major military asset in future conflicts.