London's New Year's Eve broadcasts famously use the bells of Big Ben.
Big Ben is the nickname for the Great Bell inside the Elizabeth Tower at the Palace of Westminster. In everyday speech, the name is often used for the whole clock tower, but technically the bell—not the tower or clock—is Big Ben.
The Great Bell first struck in 1859. Its hourly chime and the quarter bells form one of Britain's most recognizable soundmarks. At midnight on New Year's Eve, the twelve strikes are broadcast as the United Kingdom welcomes the new year.
The tower has undergone major conservation work, during which the bells were largely silenced except for special occasions and essential testing. The London Eye fireworks display is a separate modern celebration along the River Thames, so the landmark associated with the chimes should not be confused with the landmark used for the fireworks.