What can the onset of the Great Depression tell us about our current financial crisis? As It Happened: 1929 The Wall Street Crash explores the causes of the 1929 Wall Street Crash. Over six terrifying, desperate days in October 1929, shares crashed by a third on the New York Stock Exchange. More than $25 billion in individual wealth was lost. Later, three thousand banks failed, taking people's savings with them. Surviving eyewitnesses describe the biggest financial catastrophe in history.