The U.S. in the 1920's was a time of prosperity and change but quickly declined into the Great Depression. The Great Depression, which changed the U.S. tremendously, occurred from 1929-1941. The Great Depression was a time period in United States history in which the American dream was temporarily shattered due to the stock market crash of 1929 and several economic issues. The Great Depression was instead a great surprise; nobody expected such a powerful country's economy to collapse. At that point, the vision of the American dream began to fade away. What America needed was a strong leader, which they voted for in the 1933 presidential election. President Franklin Delano Roosevelt. President Roosevelt pledged himself to pull the United States out of depression. With the help of the New Deal and the Social Security Act, he did.