http://amarginofsafety.com/2012/02/24/a-herd-of-grey-swans/
Check out:
#5: Unrest as Iran develops a nuclear weapon (almost there);
#6: A Chinese economic implosion;
#8: Public sector retirement default (Puerto Rico is closing in);
#9: Significant unrest in the Muslim world due to US withdrawal (Benghazi, ISIS, etc.); and (drumroll)
#10: Something unexpected from North Korea;
No one can predict the future (though some believe they can). The best we can do is study history and analyze the present to try to understand the range of possibilities and the magnitude of their outcomes and hedge and buy insurance when hedges and insurance are inexpensive.