Cops vs UFOs: Hear first-hand accounts from seasoned, decorated police officers who have had unbelievable, but substantiated UFO encounters. (S1, ep 1)

Russian Roswell: An exploration of the facts and myths surrounding the Soviet-era UFO research programmes at Kapustin Yar. (S1, ep 16)

Real UFOs: A look at the secret flying saucers designed by the military around the world. Sightings in the US, South Africa, Russia, Australia and Canada have all given the locals a fright.

Mexico's Roswell: In 1974, the US government was tracking a UFO when it disappeared over Coyame, Mexico. At the same time, a civilian plane crashed. Why was it all covered up? (S1, ep 14)

Britain's Roswell: In December 1980, Air Force personnel witnessed strange lights hovering above the English countryside. Did they have a close encounter with alien spacecraft? (S1, ep 13)

Brazil's Roswell: In 1977, a remote Brazilian island was visited nightly by strange flying objects, leaving people with bizarre puncture marks and blood loss. What happened? (S1, ep 12)

Beyond The War Of The Worlds: HG Wells' classic tale of a Martian invasion has terrified audiences for more than 100 years. The history of its many retellings is revealed. (S1, ep 11)

Some experts claim that UFO wreckage is stored in a top-secret facility in Dayton, Ohio. Former employees spin a tale of alien bodies and flying saucer debris. (S1, ep 10)

Texas' Roswell: In April 1897, an unidentified craft crashed in Aurora, Texas. Locals claimed they buried the spaceship and its alien pilot. Can a new search uncover the remains? (S1, ep 9)

Cattle Mutilations: The bloodless murder of livestock has plagued farmlands worldwide for generations. Are extraterrestrial beings responsible? (S1, ep 8)