The problems of the euro turned critical when the Greek government nearly defaulted in May 2010 and the International Monetary Fund and European Union agreed to a bailout. In truth, the 17-nation euro area had deep troubles long before that. Its oversized and undercapitalized banks, its common monetary policy but diverse and fragmented fiscal policies, the persistent economic imbalances among nations that use the euro, and a cumbersome decision-making structure all made the euro-area economy vulnerable. The crisis, which still bears the mark of the Greek tragedy that first set it off, has now spread far beyond Greece.