Big Ben is the nickname for the Great Bell of the clock at the north end of the Palace of Westminster in London and is usually extended to refer to both the clock and the clock tower. The official name of the tower in which Big Ben is located was originally the Clock Tower, but it was renamed Elizabeth Tower in 2012 to mark the Diamond Jubilee of Elizabeth II.

The tower was designed by Augustus Pugin in a neo-Gothic style. When completed in 1859, its clock was the largest and most accurate four-faced striking and chiming clock in the world. The tower stands 315 feet (96 m) tall. Its base is square, measuring 39 feet (12 m) on each side. Big Ben is the largest of the tower’s five bells and weighs 13.5 long tons.

The tower is a British cultural icon recognised all over the world. It is one of the most prominent symbols of the United Kingdom and parliamentary democracy, and it is often used in the establishing shot of films set in London. The clock tower has been part of a Grade I listed building since 1970 and a UNESCO World Heritage Site since 1987.