World War I, which lasted from 1914 to 1918, was one of the most monumental events in world history. The main causes of this conflict are complex and varied, including political, social and economic factors. One of the main causes is increasing nationalism in various European countries. Countries like Germany and France have deep rivalries, generating tension and hostility. In addition, the alliances that were formed, such as the Triple Alliance (Germany, Austria-Hungary, and Italy) and the Triple Entente (France, Russia, and Britain), blurred the lines between local and global conflicts. Imperialism also played an important role in fueling tensions. European countries competed to control colonial territories, including in Asia and Africa. These tensions were further fueled by incidents such as the assassination of Archduke Franz Ferdinand of Austria, which occurred on 28 June 1914, which ultimately became the immediate trigger for the outbreak of war. The impact of World War I was far-reaching and profound. Directly, the war resulted in the deaths of approximately 10 million soldiers and more than 7 million civilians. Battles on multiple fronts, such as at the Somme and Verdun, marked brutal and horrific war tactics, having a deep psychological impact on the generations involved. In addition to loss of life, the war also destroyed a large amount of infrastructure, resulting in significant economic losses. Politically, World War I brought down many empires, such as the Austro-Hungarian Empire and the Ottoman Empire, causing changes in the political map of Europe. The 1919 Treaty of Versailles that ended the war imposed heavy sanctions on Germany, which later led to discontent and an economic crisis in the country. On the social side, World War I also caused major changes in gender roles. Many women took over jobs left by men who went to war, later contributing to the women’s suffrage movement. In addition, the war sparked new ideological movements such as communism and fascism, which influenced political currents in Europe and beyond. The long-term impacts of World War I continued and were highly influential in shaping global history, including the emergence of World War II less than twenty years later. The social, political and economic transformations brought about by this conflict have ushered the world into a modern era full of dynamics. The phenomenon of globalization, which grew along with the development of technology and communications after the war, has had a significant impact on the way of life and relations between countries in the world today.