The Progressive Era marked a time of economic growth for the United States, advancing to the Roaring Twenties.However,the Wall Street Crash of 1929 led to the Great Depression[9],a time of economic downturn and mass unemployment. Consequently,the U.S.government established the New Deal,a series of reform programs that intended to assist those affected by the Depression.The New Deal had varied success.However,once the U.S.entered World War II in December 1941,the economy quickly recovered,so much that the U.S.became a world superpower by the dawn of the Cold War.During the Cold War,the U.S.and the Soviet Union were the world's two superpowers,but with the end of the Cold War and the collapse of the Soviet Union,the United States became the world'sonly superpower.The Progressive Era marked a time of economic growth for the United States, advancing to the Roaring Twenties. However, the Wall Street Crash of 1929 led to the Great Depression[9], a time of economic downturn and mass unemployment. Consequently, the U.S. government established the New Deal, a series of reform programs that intended to assist those affected by the Depression. The New Deal had varied success. However, once the U.S. entered World War Ⅱ in December 1941, the economy quickly recovered, so much that the U.S. became a world superpower by the dawn of the Cold War. During the Cold War, the U.S. and the Soviet Union were the world’s two superpowers, but with the end of the Cold War and the collapse of the Soviet Union, the United States became the world’sonly superpower