Forbidden Caves: Could Earth's deepest caves hide secret conduits to other worlds? Or harbour evidence that aliens once visited our planet? Experts investigate. (S7, ep 3)

Aliens And Mysterious Mountains: Throughout time, people have believed mountains were the home of the divine. But could these hilltop spirits have been extraterrestrials? (S6, ep 3)

Beyond Nazca: Ancient alien theorists explore the mysterious phenomena of the Nazca Lines. Could these huge geoglyphs in Southern Peru have an extraterrestrial connection? (S5, ep 3)

The Greys: Experts investigate the 'greys' - mysterious beings with big heads and eyes found carved into rocks. Who are these strange figures and what inspired them? (S4, ep 3)

Aliens And Sacred Places: Experts explore evidence suggesting Mecca's Grand Mosque and Jerusalem's Temple Mount were the ancient meeting places of man and extraterrestrials. (S3, ep 3)

Mysterious Places: From Mexico's mystifying Zone of Silence, to Markawasi Plateau in Peru, known for its frequent UFO sightings, were these the homes of ancient aliens? (S2, ep 3)

Aliens B.C: Experts investigate whether the stories of a time when gods and otherworldly beings inhabited the planet are more than mere mythology. (S8, ep 2)

Alien Resurrections: Ancient alien theorists delve into the incredible stories of people who claim they mingled with celestial beings while they were on the brink of death. (S7, ep 2)

Aliens And The Lost Ark: Theorists investigate whether sought-after religious relic the Ark of the Covenant could hold connections to our extraterrestrial past. (S6, ep 2)

Prophets & Prophecies: Did prophets such as Elijah and Joseph Smith communicate with a heavenly source or did they actually come into contact with extraterrestrials? (S5, ep 2)