Bank of America's Transforming World Atlas has loads of lovely infographics in it, but one of the most colourful is a map of the world's riskiest sovereign debt.The map uses the prices of credit-default swaps, which are derivatives that pay out if a borrower defaults.Here's the map:BAML Sovereign credit-default swaps have been used as a type of insurance against sovereign governments not paying back the money they owe. As with any insurance product, the more expensive it is, the more likely the event you're insuring against will happen soon.