On Tuesday October 29th, 1929, Wall Street witnessed a 13% decline in the Dow Jones, an episode that became known in financial mythology as “Black Tuesday.” It is generally recognized that Black Tuesday was the beginning of the Great Depression.
http://www.gold-eagle.com/article/black-tuesday-october-29th-1929-revisited
The Dow Jones Industrial Average (DJIA) fell exactly 508 points to 1,738.74 (22.61%). In Australia and New Zealand, the 1987 crash is also referred to as Black Tuesday because of the time zone difference.
https://en.wikipedia.org/wiki/Black_Monday_(1987)
The most catastrophic stock market crash in the history of the United States, Black Tuesday took place on October 29, 1929 and was when the price of stocks completely collapsed. It was because of this day that the Roaring Twenties came to a stumbling halt and, in its place, was the Great Depression.
http://www.blacktuesday.org/
It’s really that simple or so we are told. Black Tuesday had such an impact that the market did not recover from the lows of 1929 until 1954, long after WWII, 25 years later! “A veritable bedlam of activity reigned in leading stock brokerage houses in Seattle today as the greatest avalanche of security selling known to history was launched on New York exchanges.
http://www.gold-eagle.com/article/black-tuesday-october-29th-1929-revisited
The stock market advanced significantly, with the Dow peaking in August 1987 at 2,722 points, or 44% over the previous year's closing of 1,895 points. Further financial uncertainty may have resulted from the collapse of OPEC in early 1986, which led to crude oil price decreasing by more than 50% by mid-1986.
https://en.wikipedia.org/wiki/Black_Monday_(1987)
Then all of a sudden, on Black Tuesday, the rug was pulled out from under the feet of the market. The masses lost faith in the value of stocks and opted to sell -- all at the same time! This caused a panic. Stocks started to decline precipitously, leading to more selling.
http://www.gold-eagle.com/article/black-tuesday-october-29th-1929-revisited
The Black Monday decline was—and currently remains—the largest one-day percentage decline in the DJIA. (Saturday, December 12, 1914, is sometimes erroneously cited as the largest one-day percentage decline of the DJIA.
https://en.wikipedia.org/wiki/Black_Monday_(1987)
FTSE 100 Index (July 19, 1987, to January 19, 1988). In finance, Black Monday refers to Monday, October 19, 1987, when stock markets around the world crashed, shedding a huge value in a very short time.
https://en.wikipedia.org/wiki/Black_Monday_(1987)
Also, the futures market in Chicago was even lower than the stock market, and people tried to arbitrage that. The proper strategy was to buy futures in Chicago and sell in the New York cash market. It made it hard – the portfolio insurance people were also trying to sell their stock at the same time.
https://en.wikipedia.org/wiki/Black_Monday_(1987)
After the war ended everyone was feeling free and at liberty to do whatever they wanted and to have a good time. The people were spending more and more and the banks were lending more and more out. After a period of time the banks had no more money to lend out and started to recall the loans.
http://theroaringtwentieshistory.blogspot.com/2010/06/story-of-black-tuesday-and-end-of.html
why did black tuesday happen
The black Tuesday happened because of the time zone difference.  Black Tuesday happens because of the time zone difference.