The Houses of Parliament are only a short walk down Whitehall from Trafalgar Square to Parliament Square. The building is stunning from Parliament Square, but it's worth taking a walk over Westminster Bridge and getting the view from the South Bank. Note, Big Ben is actually the name of the bell in the clock tower (St. Stephen's Tower), which chimes every 15 minutes.
The UK Parliament is one of the oldest representative assemblies in the world. The site of the Houses of Parliament is the Palace of Westminster, a royal palace and former residence of kings. Edward the Confessor had the original palace built in the eleventh century. The layout of the Palace is intricate, with its existing buildings containing nearly 1200 rooms, 100 staircases, and well over 3 kilometers (2 miles) of passages. Among the original historic buildings is Westminster Hall, used nowadays for major public ceremonial events.
Tours inside the Houses of Parliament for overseas visitors are available on Saturdays throughout the year, and weekdays too during the summer recess.