The History Channel produced a video, below, explaining everything you’d like to know about the details, specs and history of British Parliament clock tower commonly known as Big Ben:
Most people call the tower Big Ben; however, this name actually refers to the large bell inside. Officially, the Clock Tower's bell is called the Great Bell though it is better known by the name 'Big Ben.’ The Clock Tower has now been renamed the Elizabeth Tower in a tribute to Queen Elizabeth in her Diamond Jubilee year. Behind-The-Scenes tours of Big Ben are available and free, but, they are Open to UK permanent residents only. However,You can see some of the inside tour photos here.
written before about souvenir replicas of Big Ben.