On this day, October 19th, in 1987, the stock market crashed. It became known as Black Monday. The crash started in Hong Kong, spread west to Europe, and made its way to the United States. The Dow Jones Industrial Average (DJIA) dropped by 508 points to 1738.74.

Potential causes for the decline in the stock markets have been identified as program trading, overvaluation, illiquidity, and market psychology. The most popular explanation was selling by program traders. Many people blamed the program trading strategies that blindly sold stocks as markets fell, which exacerbated the decline.

The terms, Black Monday and Black Tuesday, are also used with reference to October 28th and 29th in 1929.