Greece should demand Germany repay the WWII debts that they and the Allies forgave. At the end of WWII Germany's debt was 200% of its GDP. The Allies, including Greece which Germany ransacked, forgave most of it.
Of course, comparing Greece to Nazi Germany is unfair: The Greeks are guilty of economic irresponsibility, while Germany was only guilty of mass murder and world wars that killed hundreds of millions and ruined economies world-wide. http://qz.com/445373/thomas-piketty...crisy-and-how-to-solve-the-greek-debt-crisis/