On October 29, 1929, known as Black Tuesday, the Wall Street stock market crash occurred as investors began panic selling. Over 16 million shares were sold on Black Tuesday alone, causing stock prices to drop 13% and marking the beginning of the Great Depression. In the preceding weeks and months, stock prices had reached unsustainable heights in a speculative bubble, fueled by margin buying with money borrowed from brokers. The crash devastated both individual investors and financial institutions, and the stock exchange closed temporarily to prevent further panic selling from worsening the crisis.