Mass riots in Greece, Portugal and Spain predicted the American Nobel prize winner Joseph Stiglitz in the case when the youth unemployment in these countries reaches 50 per cent. Specifically for the Greek economy, he partially blames the previous government of Kostas Karamanlis and the investment bank Goldman Sachs, but most of all the international financial crisis and its consequences. The famous for his left believes economist declares to be for the devaluation of the euro and believes that the survival of single European currency is not threatened.