Black Tuesday, the climax of the 1929 Wall Street Crash, occurred on October 29, 1929.
On that day, roughly 16 million shares changed hands on the New York Stock Exchange, a record at the time. Prices fell sharply as investors rushed to sell, following heavy declines on Black Thursday, October 24, and Black Monday, October 28.
The crash did not by itself cause the entire Great Depression, but it severely damaged confidence and exposed weaknesses such as buying stocks on margin, excessive speculation, and falling industrial demand. The wider economic depression developed through several interacting causes.
A common mix-up is treating Black Tuesday as the beginning of the crash. The market had already suffered major losses before October 29, while the Dow Jones Industrial Average continued falling until reaching a low in July 1932.