Big Ben and the Clock Tower – Probably the most famous landmark of Britain, the Clock Tower (also called St. Stephens Tower) houses the world’s largest chiming four faced turret clock. Its construction was completed by 1858. This tower forms part of the north-eastern corner of the Houses of Parliament building. This tower is very often erroneously referred as “Big Ben”. Big Ben is actually the largest of the five bells within the tower. This thirteen ton Bell was named after the first commissioner of works, Sir Benjamin Hall. It was cast by the foundry, Whitechapel Bell Foundry, London. In 1834 a disastrous fire had destroyed the old palace of Westminster. The tower was begun in the rebuilding process. It is 316 feet high. The spire is built with an iron frame. This supports the weight of the bells.
The Clock Tower had the largest four faced clock until 1962 when the Allen-Bradley Clock Tower in Milwaukee, Wisconsin took its place. However the Clock Tower still remains the largest Chiming clock.
Westminster Palace – This is where both the houses of Parliament of the United Kingdom ( The House of Lords and The House of Commons) are housed. The other Government buildings in Whitehall are close by. The royal family lived where Parliament is now situated until 1512, when during Henry VIII’s reign a fire forced them to move out. However, the site remained a Royal Palace; therefore, its official title is the Palace of Westminster. Westminster Hall dates back to around 1097 A.D. The palace has been rebuilt over the centuries especially after the 1834 fire and the WW II bombing.
A tour can be arranged through your local MP. More details about the available tours of the parliament and the Clock Tower for UK visitors and overseas visitors are given in http://www.parliament.uk/about/visiting.cfm
One can also take a virtual tour through the following link – http://www.parliament.uk/about/visiting/contemporary-virtual-tour/index.htm
How to reach Westminster Palace, Big Ben -
The best option would be to take the Underground to the Westminster Tube Station on the Circle, District or Jubilee lines. Full details available at http://www.tfl.gov.uk/
Another helpful tool is the official trip/journey planner.