China's Roswell: In 1938, hundreds of mysterious stone disks were found in a cave in China. Some believe the stones are proof of contact with an alien race. Fact or fiction? (S1, ep 5)
Sightings of the 70s: Accounts from a number of UFO sightings that took place in the 1970s, including the most famous of all intergalactic crashes: Roswell.
Canada's Roswell: On 4 October 1967, dozens of eyewitnesses reported seeing what appeared to be a UFO hovering above the water's surface in Nova Scotia. Was it an alien ship? (S1, ep 3)
Alien Engineering (Part 2 of 2): Laser weapons and tele-transporters would probably all be fitted to an alien spaceship, but what if they could be used by humans too? (S1, ep 2)
Alien Engineering (Part 1 of 2): What would happen if a UFO actually did land on Earth and humans found it? Engineers create a 'spaceship' to see how alien technology could work. (S1, ep 1)
Experts investigate more strange sightings, including a silver missile travelling too quickly for pilots to pursue, and mysterious lights seen by thousands over Belgium. (S1, ep 7)
More strange stories come under the spotlight, including that of a disappearing US pilot, strange incidents in a Sicilian fishing village and a weird encounter over Germany. (S1, ep 6)
Witnesses reveal the story of a strange phenomenon in a remote Italian village. Strange objects are spotted over Sweden and a UFO is reported in Portugal. (S1, ep 5)
Witnesses are baffled as strange flying objects start appearing over Europe. Everywhere from Portugal to Romania, big questions are left unanswered. (S1, ep 4)
An Air France pilot sees a huge object over Paris, UFOs are spotted over a quiet town in Portugal, and lone drivers in Denmark experience something rather strange... (S1, ep 3)