The economic collapse known as the Great Depression was primarily triggered by the stock market crash of October 1929. This catastrophic event led to a severe contraction in the economy, resulting in widespread bank failures, massive unemployment, and a dramatic drop in consumer spending and investment. It was exacerbated by factors such as overproduction, reduced international trade due to tariffs, and the lack of a safety net for consumers and businesses. The Great Depression had lasting effects on global economies, prompting significant governmental changes like the New Deal in the United States, aimed at economic recovery and reform.