Introduction to Windsor Castle: Windsor Castle is one of the official residences of the Queen of England and the largest inhabited castle in the world. Windsor Castle is divided into three areas: upper, middle and lower. The upper area mainly includes banquet halls, doll houses and other palace furnishings. The middle area has a round tower surrounded by rose gardens, and the lower area has the Gothic-style St. George's Church. The royal flag is hoisted whenever the Queen is in the castle.