World War I, which lasted from 1914 to 1918, was a global conflict involving many countries and contributed to major changes in the political, social, and economic map of the world. The causes of this war were complex and involved various factors, ranging from military alliances to nationalism. One of the main causes of World War I was the alliance system that formed in Europe. The two main blocs, namely the Allies and the Central Powers, supported each other in complex agreements. Austria-Hungary, supported by Germany, attempted to maintain its power, while Russia, England, and France united to counter the threat. Tensions between these countries increased when the assassination of Archduke Franz Ferdinand of Austria in 1914 prompted a declaration of war. Additionally, nationalism is an important driver of these conflicts. European countries had the ambition to demonstrate their power, not only through the military, but also through colonization. The rise of nationalism in the Balkans, particularly in Serbia, sparked serious tensions and contributed to great power intervention. Ethnic conflicts and aspirations for independence brought the Balkan countries to the brink of war. Imperialism was also an important factor in the cause of World War I. Competition for colonies and resources in Africa and Asia exacerbated tensions between major powers. England and France tried to maintain their colonial power, while Germany wanted to develop its colonies. These tensions not only impact the economy but also trigger increased military competition. The impact of World War I was broad and profound. Politically, this war led to the collapse of several large empires, such as the Austro-Hungarian Empire, the Ottoman Empire, and the German Empire. The founding of new countries in Eastern Europe and changes in national borders drastically changed the political map of the world. The economy has also experienced significant changes. The war caused extensive infrastructure damage and severe financial impacts for the countries involved. Many countries were forced to take on huge debts to finance the war, which ultimately triggered an economic crisis in the following decade. From a social perspective, World War I brought major changes to society. The emergence of the women’s movement, who performed important roles in industry and service during the war, drew attention to gender equality. The revelation of the reality of war also gave rise to a stronger anti-war movement and peace thinking among society. This war also gave way to new ideologies, such as communism, which emerged after the Bolshevik Revolution in Russia in 1917. The social and political transformations that occurred after the war created a situation that favored the emergence of totalitarianism in several countries, influencing the development of world history for the following decades. Overall, World War I was a monumental event that had a long-term impact on the world order. The diverse causes of conflict and its broad impact have left a deep imprint on subsequent generations, leading the world into a time full of challenges and change.