20. United States of America (20th Century)
The United States emerged as the defining superpower of the 20th century, especially in the aftermath of World War II. America’s leadership in technology, economic growth, and military strength propelled it to the forefront of global affairs. From cultural exports like film and music to shaping international institutions and alliances, U.S. influence touched every corner of the globe. Its role in crafting the postwar world order redefined international politics for generations (via Council on Foreign Relations: U.S. Global Power).
