Madrid holds the traditional New Year's Eve countdown at Puerta del Sol.
Puerta del Sol is a major public square in central Madrid and the setting for Spain's nationally famous midnight clock chimes. People watching in the square or on television attempt to eat twelve grapes, one during each chime, as a symbol of luck for the twelve months ahead.
The square's clock is mounted on the former post office building, now the headquarters of the Community of Madrid. Its chimes are broadcast throughout Spain, making the location much more than a local gathering place.
Puerta del Sol also contains the Kilometer Zero plaque, marking the conventional starting point for measuring Spain's six main national roads. That geographic fact is separate from the New Year's ritual, but it helps explain the square's national importance.