Greece have set the date for re-run of elections of June 17th. The recent Greek elections ended in chaos, with none of the parties able to form a workable coalition. However, the new fear is that Greece will not make it to June 17th.

Since the failed elections Greeks have been taking what money they can out of the banks. Companies are moving their money overseas, as fear grips the nation. If this continues, the country will run out of cash and the system will collapse.
If that happens, then Greece will exit the Euro in an un-orderly fashion. Some economists say a Greek exit could cost $ 1 Trillion. The contagion in the markets would likely result in Italy and Spain failing shortly after.