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This book, made into a movie, takes place during World War II. Four children are sent from their home in London to the English countryside to protect them from the bombing raids. While playing hide-and-seek in the old house they stay in, the youngest girl finds a way into another world through a wardrobe.
What is "Narnia," or "The Lion, the Witch, and the Wardrobe," or "The Chronicles of Narnia?" by C.S. Lewis?