World War I, fought between 1914 and 1918, was one of the most destructive conflicts in human history. A complex mix of factors fueled this war, including bubbling nationalism, imperialism, and tight military alliances. One of the starting points of this conflict was the assassination of Archduke Franz Ferdinand of Austria on 28 June 1914 in Sarajevo. After these events, the alliance system in Europe moved quickly. Austria-Hungary issued an ultimatum to Serbia, which was populated by many ethnic Slavs. Russia’s support for Serbia sparked a reaction from Germany which supported Austria-Hungary. Once again, England and France entered the conflict to support Russia, making this war a world war. This war saw the use of unprecedented military technology, including automatic rifles, tanks, and fighter aircraft. War strategy, especially on the Western Front, was characterized by prolonged trench warfare, in which troops were trapped in poor conditions and lost many lives. The war on battlefields such as Verdun and the Somme saw millions of casualties, with no clear cutoff. Globally, this conflict extended its influence to colonies in Africa, Asia, and the Pacific. Many countries outside Europe were involved, making World War I a global conflict. In Asia, soldiers from India and Japan joined the fighting, creating new dynamics in relations between countries. This conflict ended with the Treaty of Versailles in 1919. This treaty was highly controversial, especially because it placed a heavy reparations burden on Germany. This is considered to be one of the causes that fostered feelings of resentment and conflict in Europe, which then sparked World War II in 1939. The social, political and economic impact of World War I was enormous. The Russian Revolution of 1917, the emergence of new states, and changes in the political map of Europe were some of the consequences of the war. World War I also brought major changes in society, sparking the women’s movement for voting rights with many women working in factories during the war. Using sources such as historical reports and archival documents, a deeper understanding of World War I can be gained. In a long-term perspective, this war provides valuable lessons for international diplomacy and future conflicts, marking a new era in human history.