October 29, 1929, the most notorious day of the crash, is known as Black Tuesday.
On Black Tuesday, roughly 16 million shares changed hands on the New York Stock Exchange as investors rushed to sell. Prices collapsed after weeks of instability, wiping out enormous paper wealth and intensifying public fear. The crash did not single-handedly create the Great Depression, but it became its most famous financial symbol.
The market had already suffered a sharp break on October 24, known as Black Thursday, and another major decline on October 28, known as Black Monday. The sequence matters because Black Tuesday was the culmination of several days of panic rather than an isolated event.
The downturn exposed excessive margin borrowing, weak confidence, and an economy vulnerable to falling investment. The Dow Jones Industrial Average continued declining after 1929 and did not regain its September 1929 peak until 1954. The crash’s nickname is therefore a date-specific label, not the name of the entire Depression.