Mega Cars: Whether commercial vehicles or super sports cars, these Mega Cars stand out as examples of the most extraordinary vehicles in the world.

Witnesses around the world claim to have spotted mysterious sea creatures, but are these survivors from the age of the dinosaurs or just mistaken sightings?

Thousands of crop circles have been reported. Most are dismissed as hoaxes, but could some be from another world? 

Something strange washes up on a New York beach, baby monitors reveal ghostly activity in a nursery, and a UFO saves a Russian town.

A ghost appears on the Gettysburg battlefield, a sea monster surfaces in Ireland, and UFOs are spotted over Philadelphia and The Hague.

Unwelcome Visitors: If aliens have visited Earth, what are their intentions? Do they wish to experiment on the human body, or the human mind as well? (S4, ep 8)

The Next Wave: A fascinating look at the mounting evidence that suggests UFO waves are able to penetrate the world's most closely guarded airspace at will. (S2, ep 8)

Inside UFOs: Those who claim to have been abducted by extraterrestrials give their accounts of the interior of their spacecrafts. (S4, ep 7)

Alien Skies: From mid-air abductions to near-disasters caused by unseen enemies, experts examine if we are alone in the skies over Earth. (S2, ep 7)

Seeing is Believing: For decades, governments around the world have investigated UFO sightings. How are these top-secret studies conducted? (S4, ep 6)