Black Tuesday is the commonly-used term for the catastrophic stock market crash of Oct. 29, 1929 on Wall Street, New York, USA. It was officially recognized as "The Wall Street Crash of '29" (or occasionally, "The Crash of '29"), but due to its devastating effects on the economy, this historical date later earned the ominous moniker "Black Tuesday". The crash contributed to the onset of the Great Depression.

Reasons for the collapse of the stock market are generally agreed upon by today's analysts. Prior to the crash of 1929, the city of New York had been a prosperous metropolis due to the New York Stock Exchange's position as the world's largest stock market. During this time--known as the Roaring 20s--wise investors had enjoyed prosperity, ofen to the point of excess, with few investors apparently heeding early warnings that the market could not sustain its high price levels indefinitely. Indeed, for the five years preceding the crash, the Dow Jones Industrial Average recorded a fivefold increase of values, peaking on Sept. 3, 1929 at 381.17. But ominously, during the course of the following month, the market lost a full 17% of its value.

Though a percentage of that loss was recovered during during the following week, things again took a turn for the worse, culminating in what is now known as Black Thursday on Oct. 24, 1929--a panic response that initiated a record of nearly 13 million share trades in one day.

Attempts were made to alleviate the panic and slow the mass pulling of stocks by  shareholders, including a diversionary tactic involving the purchase of large quantities of shares by Richard Whitney, vice president of the stock market exchange, on Friday, Oct. 25. However, the state of the market continued to deteriorate, and following the weekend, when the stock market reopened on Oct. 28, more investors withdrew. The following day--Black Tuesday--more than 16 million shares were traded, breaking the record set just days earlier. In one week's time, the market lost a staggering $30 million.

Debates abound to the present day on whether the crash initiated the Great Depression alone or whether other factors were already set in motion prior to 1929 that coincided with the mass pull-out observed between Black Thursday and Black Tuesday. Whether or not it was the exclusive culprit, however, there is no denying the crash's impact on both the U.S. and world economy.

Because of its impact and the ensuing devastation--including loss of jobs, homes, savings and property; suicides; deaths due to starvation, disease and lack of medical care and the temporary collapse of a number of industries--an official investigation was begun in 1931 in order to study the mechanisms of the crash and attempt to prevent such an incident in occurring in the future. This investigation was run by the Pecora Commission, established at the time by the U.S. Senate, and its findings helped create various measures aimed at prevention of another collapse. Among them were the Glass-Steagall Act, passed in 1933 and mandating a separation among commercial banks.

The U.S. did not see another crash as severe as the Crash of '29 until Black Monday, Oct. 19, 1987, with the Dow Jones Industrial Average falling 22.6%; the market, however, recovered within days of the event.