Ever since a strange object fell from the sky near Roswell, New Mexico, in 1947, controversy and conspiracy theories have brewed. Was it debris from an Air Force research project -- or an elaborate UFO cover-up? The National Archive recently declassified the last remaining files on the Roswell incident, releasing 11 boxes of evidence from a government vault. Granted a chance to examine their contents -- including film footage, photos, audio recordings, documents, and an "unidentified metallic object" -- The History Channel investigates the evidence surrounding this bizarre and mysterious occurrence. Retrace the steps of the government's investigation and hear eyewitness reports. Follow cameras as the accompany an expedition to the original crash site and hear the world's leading UFO experts discuss recent theories.