What is Big Ben?
The Houses of Parliament and Elizabeth Tower, commonly called Big Ben, are among London’s most iconic landmarks and must-see London attractions. Technically, Big Ben is the name given to the massive bell inside the clock tower, which weighs more than 13 tons (13,760 kg). The clock tower looks spectacular at night when the four clock faces are illuminated.

Big Ben facts
Each dial is seven metres in diameter.
The minute hands are 4.2 metres long (14ft) and weigh about 100kg (220lbs, including counterweights).
The numbers are approximately 60cm (23in) long.
There are 312 pieces of glass in each clock dial.
A special light above the clock faces is illuminated when parliament is in session.
Big Ben’s timekeeping is strictly regulated by a stack of coins placed on the huge pendulum.
Big Ben has rarely stopped. Even after a bomb destroyed the Commons chamber during the Second World War, the clock tower survived and Big Ben continued to strike the hours.
The chimes of Big Ben were first broadcast by the BBC on 31 December 1923, a tradition that continues to this day.
The latin words under the clock face read DOMINE SALVAM FAC REGINAM NOSTRAM VICTORIAM PRIMAM, which means “O Lord, keep safe our Queen Victoria the First”
In June 2012 the House of Commons announced that the clock tower was to be renamed the Elizabeth Tower in honour of Queen Elizabeth II’s Diamond Jubilee.

Thanks : visitlondon.com