Foundations of Atlantis, ancient astronauts and other alternative pasts

Did aliens visit ancient civilizations? Could Jesus have fathered a dynasty? Did people of the ancient world visit the Americas centuries before Columbus? The public enjoys such questions, which have spawned countless books, movies and television series, but very rarely is any actual evidence produced. According to many eager writers and television hosts, evidence for long-ago astronauts or early transatlantic voyages can be found in ancient texts. But too often sources remain obscure and some writers have altered or fabricated texts to make their case for extraterrestrials and lost civilizati