First Contact: As humanity continues to search for alien life, experts give their analysis on how close we are to First Contact. (S4, ep 20)

Alien Achilles Heel. Many believe aliens are already here on Earth. Could they be plotting an attack? And if so, can humans survive their weapons' terrifying capabilities? (S2, ep 20)

Artificial Alien Intelligence: Is biological life merely a stepping stone for a universe dominated by alien artificial intelligence? (S4, ep 19)

Top Civilian Encounters: From mass sightings in the sky to reports of alien probes found in human bodies, explore the ten most disturbing extraterrestrial encounters ever. (S2, ep 19)

Alien Communications: With light from distant stars taking millions of years to reach us, how long might it take for alien life to answer any communication sent into space? (S4, ep 18)

Countdown To Disclosure: Evidence suggests the world's governments could be on the verge of announcing everything they know about UFOs. What will this mean for our society? (S2, ep 18)

Mars: The New Frontier: With science closer than ever to proving that life once lived on Mars, is there a chance that something still exists there? (S4, ep 17)

UFO Zones: Journey to the world's hottest UFO zones, where physical and paranormal phenomenons and unidentified objects and aliens are reported with alarming frequency. (S2, ep 17)

Mass Sightings: While many UFO sightings occur in rural locations with only a single eyewitness, there have been sightings over cities witnessed by hundreds. (S4, ep 16)

Alien Bodies: Uncover the shocking truth about alien remains as experts investigate unsettling reports of extraterrestrial bodies recovered from crashed UFOs. (S2, ep 16)