Built after William the Conqueror invaded with the Normans, Windsor Castle is the Queen's preferred weekend residence. It is also the longest and largest occupied palace in Europe, home to over 500 people who live and work on the property. Visitors may tour the State Apartments, Drawing Gallery, Queen Mary's Dolls House and St George's Chapel, where Charles and Camilla were married. Surrounded by extensive parkland on a 13-acre estate, the castle sits on the top of a hill on the banks of the River Thames, about a one-hour drive from Central London.