Black Tuesday, the most infamous selling day of the 1929 Wall Street Crash, occurred on October 29, 1929.
On that day, investors traded roughly 16 million shares on the New York Stock Exchange, a record at the time. The Dow Jones Industrial Average fell about 12%, following a decline of nearly 13% on Black Monday, October 28.
The crash did not single-handedly cause the Great Depression. It exposed severe weaknesses, including speculative buying on margin, overvalued shares, falling industrial output, and fragile banks. The wider economic downturn deepened during the following years.
A common mix-up is confusing Black Tuesday with Black Thursday, October 24, the first major panic day, or Black Monday, October 28. The Dow eventually reached a low in July 1932 and did not recover its 1929 closing high until 1954.