Almost a century ago, Wall Street faced one of its darkest days with the 1929 stock market crash that sparked the Great Depression. While the Roaring Twenties roared right off a cliff, the crash left behind not just economic ruin but a treasure trove of lessons for today's investors. From the importance of diversifying your portfolio to the wisdom of keeping a cash reserve, the echoes from almost a hundred years ago still offer a few invaluable insights that can help steer modern financial strategies.