Now on top of the excellent analysis above, overlay the demographics of Europe and the impact of an aging population.  Normally you need 2.1 births per female to maintain a population.  If you can't get that (Australia has about 1.75), then you need migration to boost it.  Italy has about 1.2 births per female and much of Europe is in a similar position, so they quite simply will not have the residents to not only pay back the debt long term, but also to maintain demand and keep their economies functioning.  If Greece in particular, but most of Europe were a company, would you buy shares in it?  I know I wouldn't for a long term play!