No developed nation has ever officially defaulted on its financial obligations and Greece only avoided going bust earlier this month after the Government had asked for a debt bundling, which is in question today.
While one missed payment is not expected to trigger a wave of defaults, it is a defining moment in the Greek crisis that some European leaders fear could unravel 60 years of European integration .
Greek banks will remain shut, although about 850 branches were expected to open to pay pensions.
Regarding a referendum between staying in the Euro or not, may be taken out of their hands. Capital Economics argues; “without a strong upturn in the economy, there would still be a high chance of a Greek exit from the Eurozone in the following months or years as Greece was unable to re-access bong markets” . This could potentially lead to currency shortages and rationing of goods and fuel.
 The Guardian. ‘Greece on course to miss crucial debt repayment’. http://www.theguardian.com