Tickers ran hours behind. Police stood outside the New York Stock Exchange.

On October 24, 1929, panic selling swept Wall Street. Nearly 12.9 million shares changed hands, almost 4 million more than the previous record. Major banks bought large blocks of stock to calm the market, and it closed only slightly down.

The relief didn't last. Selling returned the next week, and on Black Tuesday, October 29, prices plunged again. From its 1929 peak to its 1932 low, the Dow lost 89% of its value and did not regain its old high until 1954.

Why it still matters: economists still debate whether the crash caused the Great Depression or signaled it, and the rules that govern markets today were shaped by those years.

Could a crash like this happen again?

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