Allied nations refer to countries that come together to support each other, especially during conflicts or wars. The most notable example is during World War II, when countries like the United States, United Kingdom, Soviet Union, and China formed a coalition against the Axis Powers, which included Germany, Italy, and Japan. These alliances were based on shared goals and mutual defense. In addition to military alliances, allied nations often collaborate on economic, political, and social issues. Organizations like the United Nations and NATO facilitate cooperation among member countries, promoting peace and security worldwide. Such alliances can help nations address global challenges more effectively.