War is a state of armed conflict between different countries or different groups within a country. It often involves organized military forces and can result in significant loss of life, destruction of property, and long-lasting social and political changes. Wars can be fought for various reasons, including territorial disputes, resource control, and ideological differences. Throughout history, wars have shaped nations and influenced global relations. Major wars, such as World War I and World War II, have had profound impacts on the world, leading to the establishment of international organizations like the United Nations aimed at promoting peace and preventing future conflicts.