Bank of America refused to rescue the 158-year-old Wall Street firm without support from Uncle Sam. The British government wouldn't let Barclays (BCS) buy Lehman Brothers and its toxic balance sheet. And Washington decided against another politically unpopular bailout. So Lehman Brothers was allowed to fail. At 1:45 a.m. on Monday, September 15, 2008, Lehman Brothers filed for Chapter 11 bankruptcy protection. What ensued was the largest and most complex bankruptcy in American history. But that doesn't do justice to the damage Lehman's demise caused the financial system.