It's one of America's most mythic UFO incidents--a 200-yardswath of debris that landed near Roswell, New Mexico. Somebelieve it was an alien craft, others that it was a secretgovernment experiment. The deeper researchers dig, the moreperplexing the story gets. It's a mystery that's endured fornearly 80 years. So what really crashed in Roswell in 1947?