London's annual New Year's Eve countdown commonly shows Big Ben, the clock tower at the Palace of Westminster.
Big Ben is technically the nickname of the Great Bell inside the tower, while the tower itself was renamed the Elizabeth Tower in 2012. In everyday speech, however, “Big Ben” is widely used for the entire landmark, including its clock faces and chimes.
London's major public celebration centers on the fireworks display along the River Thames. The display began in its modern form for the arrival of 2000 and became an annual ticketed event in later years. Big Ben's midnight chimes provide the traditional audio cue as the fireworks begin.
The tower is sometimes mistakenly identified as a separate fireworks launch site. The display is staged around the Thames, with fireworks launched from the London Eye, barges, and nearby structures depending on the year. Big Ben supplies the symbolic countdown rather than hosting the whole show.