The economic depression of the 1930s, known as the Great Depression, originated in the United States in 1929 and lasted until 1939. It was the longest and most severe depression in modern history, resulting in widespread unemployment, poverty, and deflation as gross domestic product and global trade fell sharply. The causes included stock market crashes, drought, declining asset prices, bank failures, debt deflation, and the Smoot-Hawley Tariff Act. Countries began recovering in the early-to-mid 1930s as they abandoned the gold standard and expanded their money supplies, with the U.S. recovery accelerating after 1933 under President Roosevelt's New Deal programs.