0 Monday, October 28, 1929, when the price of shares on the New York Stock Exchange lost a lot of their value, causing very serious economic problems in the US and Europe, and leading to the Great Depression of the 1930s : --
Black Monday kicked off the Depression.
1 Monday, October 19, 1987, when the price of shares on the New York Stock Exchange lost 508 points from their value, causing problems in stock markets around the world: --
2 Monday, October 27, 1997, when the price of shares on the New York Stock Exchange lost 554 points from their value, causing problems in stock markets around the world --