At Spain's Puerta del Sol, celebrants traditionally eat twelve grapes with the twelve midnight chimes.
The custom is known as las doce uvas de la suerte, or “the twelve grapes of luck.” People try to eat one grape at each stroke of the clock at midnight on December 31. Finishing all twelve is associated with good fortune for the coming year.
Madrid's clock at Puerta del Sol is the best-known national symbol of the ritual, and Spanish television broadcasts its chimes to viewers throughout the country. Families and friends often prepare twelve grapes in advance so they can keep pace with the clock.
The tradition became especially prominent in the early 20th century. A commonly cited explanation connects its spread with a surplus grape harvest, although the custom also developed from earlier upper-class New Year's practices. The grapes represent the twelve months of the year.