The Palace of Westminster is the meeting place of the House of Commons and the House of Lords, the two houses of the Parliament of the United Kingdom. Commonly known as the Houses of Parliament after its occupants, the Palace lies on the north bank of the River Thames in the City of Westminster, in central London, England.  

The first royal palace was built on the site in the 11th century, and Westminster was the primary residence of the Kings of England until fire destroyed much of the complex in 1512.  After that, it served as the home of the Parliament of England, which had been meeting there since the 13th century, and also as the seat of the Royal Courts of Justice, based in and around Westminster Hall.  

The Palace is one of the centers 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.