The 24 October 1929 session that began the most famous phase of the Wall Street Crash is commonly called Black Thursday.
On that day, heavy selling hit the New York Stock Exchange after a period of rapid speculation and rising share prices. A group of major bankers temporarily supported prices, helping calm the market, but the intervention did not end the underlying crisis.
Selling intensified on subsequent trading days. Black Monday occurred on 28 October, and Black Tuesday followed on 29 October, when approximately 16 million shares changed hands. The crash helped usher in the Great Depression, although historians identify several economic causes rather than a single trigger.
Black Thursday is sometimes confused with Black Tuesday because the latter is more strongly associated with the final panic week. The names refer to separate dates within the same 1929 market collapse.