Why Europe's banks could be the next flash point for markets

Over the weekend, the Spanish central bank stepped in to take over one of the country's regional savings banks, or 'cajas'. For now, the bank, CajaSur, will have more than €500m injected into it. In itself, the story is not huge. But the problems it points to with the rest of the Spanish banking system – not to mention the eurozone's – are far more worrying…