Big Ben is the bell whose midnight chimes from the Elizabeth Tower are broadcast on New Year's Eve in London.
Strictly speaking, Big Ben is the nickname of the Great Bell, not the tower itself. The tower is part of the Palace of Westminster, and its clock is officially called the Great Westminster Clock. The bell first struck in 1859.
Big Ben's hour bell has a distinctive low note, while four smaller bells sound the quarter-hour Westminster chimes. The midnight strike on December 31 is a familiar audio signal for the start of the new year in the United Kingdom.
The tower was called the Clock Tower until 2012, when it was renamed Elizabeth Tower in honor of Queen Elizabeth II's Diamond Jubilee. Restoration work has periodically silenced or limited the chimes, but the landmark remains central to London's national broadcasts.