Could a human being really come back from the dead to feed on human flesh and brains? If myths about zombies and other walking dead are just fictional stories, why have so many people claimed to have witnessed the return of the dead from the grave?

Could life-forms from other parts of the universe really travel all the way to Earth? If alien sightings are just fictional stories, why have so many people provided such similar accounts of encounters with extraterrestrials and their spacecraft? What would it be like to witness an alien or UFO from another world, and how can you tell if the object speeding across the sky has been sent by an advanced civilization to study--or even invade--our planet?...