|"Is this all real? Or has this been happening inside my head?"
The subject of this article is a real-life person, group, company, product, or creative work that has been mentioned "in-universe" in a canon source. The Harry Potter Wiki is written from the perspective that all information presented in canon is true (e.g., Hogwarts really exists), and, as such, details contained in this article may differ from real world facts.
The Palace of Westminster, also known as the Houses of Parliament, and found in Westminster, is the meeting place of the two houses of the Parliament of the United Kingdom. The palace retains its original status as a royal residence for ceremonial purposes. "Big Ben" is the nickname for the great bell of the clock at the north end of the Palace and is generally extended to refer to the clock or the clock tower as well.