As of 2010, these five countries are the most financially troubled of the Euro zone and are facing consequences varying from drastic austerity measures to possible forced disassociation from the Euro currency.
The crisis originated in Greece when its sovereign debt ratings were cut in December of 2009. It was later revealed in February of 2010 the Greek government hid massive amounts of debt using complex financial derivatives with the aid of US investment bank Goldman Sachs. In May of 2010, Greece was forced to implement a series of austerity measures in an effort to reduce the government's deficit in order to accept renegotiated loan agreements.
Spain later implemented austerity measures and also saw its sovereign debt ratings cut by rating firm Standard & Poors. Portugal, Italy, and Ireland were also added and now make up what is considered the five most at-risk countries of the Eurozone.