The event that marked the start of the Great Depression in the United States was the stock market crash of **1929**. This financial disaster, particularly highlighted by Black Tuesday, when stock prices collapsed, had far-reaching effects on the economy. Following the crash, businesses failed, banks closed, and unemployment soared, plunging millions into poverty. The economic downturn prompted widespread social distress and significant changes in public policy, leading to reforms under President Franklin D. Roosevelt’s New Deal. The Great Depression fundamentally reshaped America’s economic landscape and its social fabric for generations.