The soul of a nation's food: Vietnamese fish sauce
(CNN) - Fish sauce - nước mắm, or literally 'salted fish water' - is a Vietnamese culinary icon, an indispensable national ingredient up there with olive oil or soy sauce. But it's fair to say that the production process isn't the most fragrant, thanks to the pungent funk emanating from anchovies fermenting in vast wooden vats for a year.