The Cottingley Fairies Mystery

An obituary in Saturday's New York Times that mentions Arthur Conan Doyle's involvement with this photographic hoax: "Were there really fairies at the bottom of the garden, or was it merely a childhood prank gone strangely and lastingly awry? That, for six decades, was the central question behind the Cottingley fairies mystery, the story of two English schoolgirls who claimed to have taken five pictures of fairy folk in the 1910s and afterward...."