There was a time when people who believed that the government can control the weather, or that Wi-Fi causes cancer might have been social pariahs. 

Now, they sit in the higher echelons of power in the United States.

So, why are conspiracy theories flourishing now?

Today, British journalists Ian Dunt and Dorian Lynskey, authors of Conspiracy Theory: The Story of An Idea, on the history and psychological pull of conspiracy theories. And the destruction they can cause, when they move from the fringe to the mainstream.