October 29, 1929, is known as Black Tuesday, the largest one-day decline during the Wall Street Crash of 1929.
On that Tuesday, about 16 million shares changed hands on the New York Stock Exchange, setting a trading-volume record at the time. The Dow Jones Industrial Average fell 11.7%, adding to the collapse that had begun the previous week.
The crash followed years of rising share prices, widespread speculation, and purchases made with borrowed money. When confidence weakened, investors rushed to sell, but the market could not absorb the volume without sharp price declines. The crash did not by itself cause the entire Great Depression, although it intensified financial stress and damaged public confidence.
Black Tuesday is often confused with Black Thursday, October 24, and Black Monday, October 28. Black Thursday marked the first major panic, while Black Monday preceded the still steeper fall on October 29.