"The notion that UFOs are real is one that is very much alive in todays society. In fact, sightings of UFOs as well as close encounters with actual alien visitors have been reported for centuries. And for hundreds of years, such sightings were often dismissed by skeptics because the men and women who reported encounters with aliens could provide no evidence other than the stories of their experiences. But starting in the latter half of the 20th century, as audio and video recording equipment became more common in society, evidence of alien encounters could be recorded and analyzed. As a result, such evidence has gained more credibility"--.
UFOs and Alien Encounters : Are They Real?