The October 29, 1929, U.S. stock-market crash was nicknamed Black Tuesday.
Black Tuesday followed Black Thursday, the sharp sell-off on October 24, and a temporary recovery attempt on October 25 and 28. On October 29, investors traded roughly 16 million shares on the New York Stock Exchange, then an extraordinary volume for the period.
The crash did not by itself cause the entire Great Depression, but it became its most famous financial symbol. Bank failures, falling demand, debt problems, and declining industrial production deepened the economic crisis. The Dow Jones Industrial Average eventually fell about 89% from its September 1929 peak to its July 1932 low.
Black Tuesday is sometimes confused with Black Monday, the 1987 global market plunge. They were different crashes separated by nearly six decades.