The Great Depression was a severe worldwide economic depression in the decade preceding World War 2. The timing of the depression varied across nations, but in most countries it started in about 1929 and lasted till the late 1930s or early 1940s. It was the longest, most widespread, and deepest 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. The depression originated in the U.S. starting with the 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).From there it quickly spread to almost every country in the world.