The Hidden Cowboy
In 1996, Ike Clanton, dressed in cowboy attire had his friend photograph him while he stood in Boothill Graveyard in the famous Tombstone, Arizona. After reviewing the photograph, Clanton noticed a man in the background of the photo that was not there when the photograph was taken.
Clanton was intrigued by this and set out to recreate the photo with a friend standing in the background and discovered it was impossible to recreate the picture without having the legs visible. This photograph remains a mystery to this day.