Built as part of Westminister Palace in 1858 in Gothic Revival style, in time Big Ben has become one of the most prominent symbols of both London and England, as well as a well-known structure. It is also the largest four-faced chiming clock and the third largest free-standing clock tower in the world.
The nickname “Big Ben” originally denoted the great, 16-tonne bell, but it soon became associated with the whole clock-tower. In the visual media the clock has become a symbol of the United Kingdom and London – when a television or film-maker wants to highlight a generic location in Britain, a popular way to do so is to show an image of the Clock Tower, often with a red double-decker bus or a black cab in the foreground
The present-day tower was erected as part of a new palace after the old Palace of Westminster was largely damaged by fire in 1834. The whole site was designed in Gothic Revival style. The tower is 96,3 metres high; its bottom part (61 metres) consists of limestone brickwork and the remaining part is a framed spire of cast iron.
Despite being one of the world’s most famous tourist attractions, the interior of the tower is not open to overseas visitors, but UK citizens are able to arrange tours (well in advance) through their Member of Parliament. Those who are lucky enough to enter the tower, however, must climb the 334 limestone stairs to the top, as the tower has no lift.
The clock’s movement is famous for its reliability. Its dials are set in an iron frame, 7 metres in diameter, supporting 312 pieces of opal glass, like a stained-glass window. The pendulum installed within an enclosed windproof box is 3,9 metres long, weighs 300 kg and beats every 2 seconds. The clockwork mechanism in a room below weighs 5 tonnes.
On top of the pendulum there is a small stack of old penny coins; these are to adjust the time of the clock. Adding a coin has the effect of minutely lifting the position of the pendulum’s centre of mass, reducing the effective length of the pendulum rod and hence increasing the rate at which the pendulum swings. Adding or removing a penny will change the clock’s speed by 0.4 seconds per day. One of the requirements for the clock is that the first stroke of the hour bell should register the time, correct to within one second per day.
The main bell, officially known as the Great Bell, is the largest bell in the tower and a part of the Great Clock of Westminster. The original bell weighed 16,3 tonnes and was transported to the tower on a trolley drawn by sixteen horses. Unfortunately, it cracked beyond repair while being tested and a replacement had to be made.
At the time of its casting, Big Ben was the largest bell in the British Isles. It had held the title until “Great Paul”, a 17-tonne bell currently hung in St Paul’s Cathedral, was cast in 1881.