Windsor Castle has served as the summer residence of British Royals since William the Conqueror built the first fortress here in 1078. The largest inhabited castle in the world, Windsor Castle is built around two spectacular courtyards, and entrance fees include admission to the State Apartments (closed when The Queen's at home, so check whether the royal flag's flying). Also of note is the wonderful Great Park, a magnificent 6 mi-long park that most North American visitors will already have seen from the air as they fly into Heathrow. And, of course, no visit to a royal palace would be complete without witnessing the Changing the Guard in the Castle Precincts.
