The First World War, also known as World War I, was a global conflict that lasted from 1914 to 1918. It involved many of the world's great powers, divided into two main alliances: the Allies and the Central Powers. The war was triggered by the assassination of Archduke Franz Ferdinand of Austria-Hungary and was characterized by trench warfare and significant military innovations. The conflict resulted in an estimated 16 million deaths and led to major political changes in many countries. The war ended with the signing of the Treaty of Versailles in 1919, which imposed heavy reparations on Germany and redrew national boundaries in Europe.