The major conflict known as the Great War before World War II was World War I, which lasted from 1914 to 1918. This global conflict primarily involved two opposing military alliances: the Allies, including France, the United Kingdom, and Russia, and the Central Powers, notably Germany, Austria-Hungary, and the Ottoman Empire. The war was characterized by trench warfare, significant loss of life, and widespread destruction. World War I profoundly reshaped political boundaries and led to the downfall of empires, such as the Austro-Hungarian and Ottoman Empires. Additionally, the Treaty of Versailles in 1919 imposed reparations and territorial losses on Germany, sowing the seeds of political and economic unrest that contributed to the rise of World War II.