Modern World War generally refers to military conflicts that took place in the 20th and 21st centuries. The two most significant major wars in this period were World War I (1914-1918) and World War II (1939-1945). Each of these wars brought about major changes in world order, geopolitics, and developments in military technology. World War I began as a result of various factors, including nationalism, imperialism, and complex alliances between European countries. This conflict resulted in more than 16 million deaths and devastated many countries. Modern weapons such as machine guns, fighter planes, and poison gas were widely used, changing the way war was fought. The Treaty of Versailles in 1919 ended the war, but also aroused discontent, especially in Germany. World War II began as a result of waning tensions during the antiwar period, including the rise of totalitarianism in Germany, Italy, and Japan. Germany’s attack on Poland in 1939 was the starting point of this global conflict. The conflict involved more than 100 million people from more than 30 countries, seeing iconic battles such as the Battle of Stalingrad and D-Day. The war was marked by unprecedented atrocities, including the Holocaust genocide and the use of nuclear weapons by the United States in Hiroshima and Nagasaki. These two wars caused a transformation of the world’s political map. The UN was founded in 1945 to prevent a recurrence of this type of conflict. During the Cold War, the world was divided into two large blocs: the western bloc led by the United States and the eastern bloc led by the Soviet Union. This tension marks a new era of ideological and proxy conflict in various parts of the world. Modern warfare marks a transition to more complex conflicts, embracing phenomena such as asymmetric warfare, terrorism, and the use of advanced technologies such as drones. New concepts in warfare and military strategy continue to develop, adapting to the dynamic geopolitical context. In the last decade, armed conflicts such as those in Syria, Ukraine and Yemen remind us of the impact of modern war. Global society is now more connected, necessitating more effective diplomatic solutions. Education about these conflicts, as well as peace efforts, is essential in avoiding historical mistakes. Since 2000, many countries have paid attention to the social and economic impacts of armed conflict. International initiatives to prevent war and support sustainable development are increasing along with awareness of the factors underlying conflict. In addition, information technology has changed the way society interacts with news and information about war, having implications for public opinion and government policy. Overall, Modern World War is not just about weapons and strategy; it also reflects social, economic, and political dynamics that will continue to influence future generations. Through a better understanding of the history of these wars, there is hope for creating a more peaceful and stable future throughout the world.