Ill start with a few facts.  The huge tower is over 300 feet tall, with the belfry comprising almost 2/3 of it.  To get to the clock room, you must climb almost 300 steps, and climb almost 350 to get to the belfry.  There are 4 bells, all in the key of F, that sound each fifteen minutes.  The single bell that rings on the hour, which was nicknamed Big Ben before the tower took on the name, weighs over 13 ½ tons.  The four faces of the clock are each about 23 feet across, contain 312 separate panes of glass for easy replacement, and use almost thirty light bulbs to illuminate them from behind.  The hour hands are nine feet long, the minute hands are fourteen feet long, and the Roman numerals encircling the faces are two feet long.

            On October 16, 1834, the Palace of Westminster that was in the spot of the current Palace burnt to the ground in the late evening.  Since Great Britain needed a new building to house their Parliament, a contest was set up between competing architects.  In the end, Charles Barry won.  His design was the only one to include a clock tower.

 Charles Barry invited a famous clockmaker named Benjamin Lewis Vulliamy to design the tower and estimate the cost.  However, Vulliamy was not the only contender.  Sir George Airy was appointed to judge the best design.  The most important requirement was that the first chime on every hour be within one second of the correct time.  Besides Vulliamy, two other competitors, Dent and Whitehurst, where in close competition.  In 1852, Dent was chosen to be the architect of the clock tower.

Dent made a mistake in his designs for the clock mechanism, though.  It was too large to fit inside of the tower, and the mechanism had to be redesigned.  Edward Dent, the man who started work on the clock mechanism, died in 1853.  His stepson, Frederick Rippon, finished it.  It was completed in 1854, but could not be put to use because the tower to house it wasnt done yet.  Therefore, Edmund Denison, another important figure in the creation of the mechanism, could tinker with it for awhile.  Because of this, Denison invented the double three-legged gravity escapement, which is what keeps the clock on almost perfect time.

Edmund Denison was also allowed to provide specifications for the many bells.  John Warners and Sons was given the contract and made the huge hour bell in 1856.  It was supposed to weigh fourteen tons, but, in the end, it weighed sixteen tons.  Then, Denison decided to increase the weight of the hammer by 50%.  This caused the bell to form a huge crack the next year in 1857.  The Whitechapel Bell Foundry melted the ruined bell down and produced a new one that is still in use today.  The first bell was the first thing to be nicknamed Big Ben.  This is thought to have originated from the Commissioner of Works at John Warners and Sons, Benjamin Hall.

In 1912, an electric motor was installed to wind the clock.  This task had previously taken two men over five hours to complete.  Both in 1934 and 1956, the clock mechanism was completely overhauled.  In 1976, a horrible event occurred that could have destroyed the entire clock mechanism.  At a quarter til four oclock in the morning on August 5, 1976, a metal shaft inside of the clock broke, causing the bells to chime out of control.  Debris was thrown everywhere, even going completely through the ceiling, floor, and clock faces.  Luckily, the clock was shut down.  It took over a year to repair.

Big Ben is by far the most famous clock in the world.  It has inspired an alarm clock brand, been featured in countless movies, and even become the name of a volcano in the tropics.  The Clock Tower has become the symbol of London and Great Britains power and stability.

Sources:

            http://www.bigben.freeservers.com

            http://en.wikipedia.org/wiki/Big_Ben