Big Ben's clock is traditionally heard during the BBC's New Year's Eve broadcast from London.
Big Ben is the nickname for the Great Bell in the Elizabeth Tower at the Palace of Westminster. The tower and clock were completed in the 19th century, and the bell first struck in 1859. Technically, Big Ben refers to the bell, not the entire tower or clock mechanism.
At midnight, the clock's chimes are used as an audio marker for the beginning of the new year. Television coverage commonly pairs the sound of the chimes with views of fireworks over the River Thames and the London Eye.
The tower was officially renamed the Elizabeth Tower in 2012 in honor of Queen Elizabeth II's Diamond Jubilee. Many people still use Big Ben for the whole landmark, but that everyday usage differs from the technically precise name.