Black Tuesday was Oct. 29, 1929, and it was marked by a sharp fall in the stock market, with the Dow Jones Industrial Average (DJIA) especially hard hit in high trading volume. The DJIA fell 12%, one of the largest one-day drops in stock market history. More than 16 million shares were traded in the panic sell-off, which effectively ended the Roaring '20s and led the global economy into the Great Depression.