The "Grand Alliance" refers to the coalition formed during World War II, primarily consisting of the United States, United Kingdom, and Soviet Union. This alliance was established to combat the Axis powers, which included Germany, Italy, and Japan. The collaboration among these nations was crucial in coordinating military strategies and resources to achieve victory. The Grand Alliance was characterized by its diverse ideologies and goals, as the Soviet Union had a communist regime, while the United States and United Kingdom were democratic nations. Despite their differences, the urgency of defeating the Axis powers united them, leading to significant military successes, including the D-Day invasion and the eventual defeat of Nazi Germany.