<P> The Wall Street Crash of 1929, also known as Black Tuesday (October 29), the Great Crash, or the Stock Market Crash of 1929, began on October 24, 1929 ("Black Thursday"), and was the most devastating stock market crash in the history of the United States (acting as the most significant predicting indicator of the Great Depression), when taking into consideration the full extent and duration of its after effects . The crash, which followed the London Stock Exchange's crash of September, signalled the beginning of the 12 - year Great Depression that affected all Western industrialized countries . </P> <P> The Roaring Twenties, the decade that followed World War I and led to the crash, was a time of wealth and excess . Building on post-war optimism, rural Americans migrated to the cities in vast numbers throughout the decade with the hopes of finding a more prosperous life in the ever - growing expansion of America's industrial sector . While the American cities prospered, the overproduction of agricultural produce created widespread financial despair among American farmers throughout the decade . This would later be blamed as one of the key factors that led to the 1929 stock market crash . </P>

When did the stock market crash causing the great depression