We live in a world of more frequent terrorist attacks, political upheaval, sectarian warfare and natural disasters. Many of these events occur when markets are closed, but they can have a wide-ranging and immediate influence on the direction of equity markets. As has been the case in almost all the moments of crisis that the U.S. stock market has had to contend with, with each blow-off brought about by panic selling, the major averages have recovered within a relatively short period of time thereafter.