The major event that took place during the autumn of 1929 leading to the Great Depression was the stock market crash. Specifically, Black Tuesday, on October 29, 1929, marked the most significant drop in stock prices, resulting in massive financial losses. Investors lost confidence, leading to widespread bank failures and economic turmoil. The crash acted as a catalyst for the global economic decline that followed, characterized by soaring unemployment rates, business bankruptcies, and a significant contraction in consumer spending. It ultimately set the stage for the prolonged economic crisis known as the Great Depression, which lasted throughout the 1930s.