<P> The Great Depression was a severe worldwide economic depression that took place mostly during the 1930s, beginning in the United States . The timing of the Great Depression varied across nations; in most countries it started in 1929 and lasted until the late - 1930s . It was the longest, deepest, and most widespread depression of the 20th century . In the 21st century, the Great Depression is commonly used as an example of how far the world's economy can decline . </P> <P> The Great Depression started in the United States after a major fall in stock prices that began around September 4, 1929, and became worldwide news with the stock market crash of October 29, 1929 (known as Black Tuesday). Between 1929 and 1932, worldwide gross domestic product (GDP) fell by an estimated 15% . By comparison, worldwide GDP fell by less than 1% from 2008 to 2009 during the Great Recession . Some economies started to recover by the mid-1930s . However, in many countries, the negative effects of the Great Depression lasted until the beginning of World War II . </P> <P> The Great Depression had devastating effects in countries both rich and poor . Personal income, tax revenue, profits and prices dropped, while international trade plunged by more than 50% . Unemployment in the U.S. rose to 25% and in some countries rose as high as 33% . </P>

When did the great depression begin and why