Watch HDToday. Filmed over the course of a year in an "upstairs-downstairs" fashion, this fascinating program provides a behind-the-scenes look at life inside Windsor Castle -- the world's largest inhabited castle -- via unprecedented camera access. Highlights include a visit from French President Jacques Chirac; the Queen's arrival for the Order of the Garter ceremony; and the high-profile celebration of Prince Charles and Camilla Parker Bowles's nuptials.