Ever since Erich Von Daniken released Chariots of The Gods in the 70's, a fair number of people believe that aliens came to earth during our world's formative years. While there have been movies (i.e. "In Search of Ancient Astronauts") and TV shows (i.e. In Search Of.....) that tried to present both sides of the argument, History Channel's current series, Ancient Aliens, really takes the cake. 13 seasons and counting, all in the space of less than a decade (cable seasons are way shorter than broadcast networks, and they can have as many as three "seasons" in one calendar year).
Local product Kevin Burns, from Schenectady, now working & living in Los Angeles, is the brains behind this series, and Von Daniken has been a frequent contributor, still going strong at 83. I honestly think part of the reason this show is on the air is the success of Chris Carter's The X-Files during its initial run in the 90's and early '00's. There are people who believe that aliens have visited Earth in some form in recent decades, but proof is hard to come by organically (meaning, there usually isn't any) without skeptics alleging a scam.
Personally, while there are facts that debunk claims of aliens having been involved in landmarks such as the pyramids in Egypt, there are the believers who think otherwise, and I'd offer them a Bible and a DVD set of either Star Trek, My Favorite Martian, or Mork & Mindy to challenge what common sense they have left.
Burns, by the way, does have a sci-fi pedigree. His production company was responsible for a movie and subsequent TV show a few years back that those same believers should be checking out. Alien Nation.
Here's a recent episode:
Somehow, I can't watch this without thinking of a soundtrack that includes "Weird" Al Yankovic, Thomas Dolby ("Aliens Ate My Buick"), and pieces of Looney Tunes.