Anyway, that's a long way of saying I don't have time to deal with this topic, myself, in the way I'd like to. So, here, from PBS's American Experience website. I'll point out the money quote because I know it's too much for someone like you to read two short paragraphs
... the Klan disbanded. Nearly 50 years later, in 1915, "Colonel" William Joseph Simmons, revived the Klan after seeing D. W. Griffith's film Birth of A Nation, which portrayed the Klansmen as great heroes.
Update: And from the BBC:
Update: Well, dear, apparently it's too complex for you guys to fathom but let me point out something about how that thing called "time" works. 1915 came before the 1920s. An event that happened in the 1920s couldn't have an effect on events in 1915 but an event, a major event, a major event in the culture would be expected to have effects on the period that came soon after that event. Really, you people are stupider than Gerald Ford was ever accused of being. I take that back, you're stupider than Dan Quayle, and that's plenty stupid enough to be getting on with.
Didn't they teach you how the counting numbers worked in the early elementary school years?