Among these is a tradition with old roots and a new wave of popularity—eating 12 grapes at midnight. Known as the 12-Grape Theory, the custom promises good fortune for the coming year ...

Can grapes bring you luck? Spaniards believe so, and at midnight on New Year's Eve all across the country it's a race to gobble 12 grapes all before the first minute of the year passes.

Some cheer, or wish their loved ones a happy new year. And others crawl under a table and race to shove a dozen grapes in their mouths in under one minute. The ritual has a few variations ...