6x1 - History's Greatest Mysteries

It's one of America's most mythic UFO incidents. A 200-yard swath of debris that landed near Roswell, New Mexico. Some believe it was an alien craft, others that it was a secret government experiment. The deeper researchers dig, the more perplexing the story gets. It's a mystery that's endured for nearly 80 years. So what really crashed in Roswell in 1947?