An economic historian is studying a period in the early 20th century characterized by a sudden, severe stock market collapse. This event was followed by a wave of bank failures as panicked citizens rushed to withdraw their savings. Over the next several years, industrial production plummeted, and unemployment rates soared to unprecedented levels, affecting nations worldwide. Businesses struggled with falling prices for their goods, leading to further layoffs and closures. Based on the characteristics described, which major 20th-century economic downturn is the historian most likely studying? Explain your reasoning by connecting specific details from the text to the historical event.