Lehman shock still reverberating five years on
That event sparked a financial crisis that has taken a long time to recover from and is central to most of the problems that the global banking system is still trying to grapple with, not least the availability of credit in most of the developed world.
The US Treasury and the Federal Reserve did their utmost to protect the survival of the venerable institution, but eventually decided there was a price beyond which it was not worth paying. They did not realise the carnage that would ensue following its collapse and it is pretty clear that if they did, they probably would have adopted a vastly different approach.