World War I, which occurred between 1914 and 1918, was a global scale conflict involving many countries. The factors causing this war are very complex and cover various aspects, such as political, economic and social. One of the main factors is nationalism. Many countries in Europe at the time were experiencing an intense revival of nationalism. Countries such as Germany, France and Austria-Hungary sought to strengthen their national identity. Territorial ambitions were also a trigger, especially in the Balkans, where Serbia wanted to break away from Austro-Hungarian rule. Military alliances also play an important role. Germany, Austria-Hungary, and Italy formed the Triple Alliance, while France, Russia, and England formed the Triple Entente. Tensions between these two blocs increase the potential for conflict. After the assassination of Archduke Franz Ferdinand in 1914, Austria-Hungary declared war on Serbia, which then attracted Russia as a Serbian ally. This resulted in a prolonged war. Additionally, imperialism played a big role. European countries competed for colonies and resources around the world, creating tensions between countries. Britain and Germany, for example, competed for influence in Africa and Asia. This conflict encourages countries to carry out military mobilization. The impact of World War I was broad and profound. Directly, the war caused more than 16 million deaths and millions of injuries. Additionally, the war damaged many economies in Europe, resulting in inflation and unemployment. Many countries have struggled to rebuild infrastructure destroyed by war. From a political perspective, World War I was also a catalyst for major change. The Austro-Hungarian, Ottoman, and Russian empires collapsed, triggering revolutions in many countries. The formation of the League of Nations in the early 1920s aimed to prevent the recurrence of similar conflicts, although it was not very successful. The social impact is no less significant. The war sparked major changes in gender roles, with many women taking over jobs previously reserved for men. This accelerated the movement for voting rights for women in various countries, who were previously marginalized in the political sector. Post-war tensions intensified with the Treaty of Versailles, which was imposed on Germany. The heavy sanctions that were applied actually created a deep sense of dissatisfaction and resentment, which later became one of the factors in the emergence of World War II. Therefore, World War I was not just a matter of battle and military strategy, but was also related to fundamental changes in the structure of society and global geopolitics.