The severe worldwide economic downturn that followed the 1929 stock-market crash is known as the Great Depression.
It began in the United States in 1929 and spread internationally during the early 1930s. Industrial output, employment, trade, prices, and bank lending fell sharply in many countries. In the United States, unemployment reached about 25 percent in 1933, though measurements vary by definition and country.
The Wall Street crash was an important trigger and symbol, but it was not the sole cause. Banking failures, debt burdens, deflation, reduced consumer demand, protectionism, and monetary contraction all amplified the downturn. The gold standard also transmitted financial pressure across borders.
The Great Depression is distinct from the Great Recession, the global downturn associated with the 2007–09 financial crisis. It is also distinct from the Long Depression, a nineteenth-century period of economic weakness often dated from the 1873 financial panic.