October 24, 1929, was called Black Thursday, the first major panic day of the Wall Street Crash of 1929.
Heavy selling overwhelmed the New York Stock Exchange, and the Dow Jones Industrial Average fell 11.7%. A group of leading bankers later bought large blocks of shares to calm the market, producing a temporary recovery.
Black Thursday is often confused with Black Tuesday, October 29, when the Dow suffered another enormous sell-off. The crash did not happen on one day: prices had already weakened after peaking in September, and further collapses occurred in late October and afterward.
The 1929 crash helped deepen the Great Depression, although historians generally describe the relationship as complex rather than treating the crash alone as its sole cause. The Dow eventually lost almost 89% from its 1929 peak to its 1932 low.