World War I began on July 28, 1914, following the assassination of Archduke Franz Ferdinand of Austria-Hungary, which triggered a series of alliances and conflicts among major European powers. Nationalism, militarism, and a complex web of treaties led to escalating tensions. The war quickly engulfed multiple countries, as the Allies, including France, Russia, and the United Kingdom, confronted the Central Powers, led by Germany and Austria-Hungary. This global conflict saw unprecedented levels of destruction and loss of life, ultimately reshaping the political landscape of Europe and leading to profound changes, including the Treaty of Versailles and the rise of new political ideologies.