Houses of Parliament -The Palace of Westminster, also known as the Houses of Parliament or Westminster Palace, is the meeting place of the two houses of the Parliament of the United Kingdom—the House of Lords and the House of Commons. It lies on the north bank of the River Thames in the heart of the London borough of the City of Westminster, close to the historic Westminster Abbey and the government buildings of Whitehall and Downing Street. The name may refer to either of two structures: the Old Palace, a medieval building complex, most of which was destroyed in 1834, and its replacement New Palace that stands today.
The palace retains its original style and status as a royal residence for ceremonial purposes. The first royal palace was built on the site in the eleventh century, and Westminster was the primary London residence of the Kings of England until a fire destroyed much of the complex in 1512. After that, it served as the home of Parliament, which had been meeting there since the thirteenth century, and the seat of the Royal Courts of Justice, based in and around Westminster Hall.
The Palace is one of the centres of political life in the United Kingdom; "Westminster" has become a metonym for the UK Parliament, and the Westminster system of government has taken its name after it. Its Clock Tower, in particular, which has become known as "Big Ben" after its main bell, is an iconic landmark of London and the United Kingdom in general, one of the most popular tourist attractions in the city and an emblem of parliamentary democracy.
Source & More Information: Wikipedia, Palace of Westminster, http://en.wikipedia.org/wiki/Palace_of_Westminster