I find the Ku Klux Klan fascinating. They seem quite insane, yet at times in our history, they were very popular and in areas of the country that I would not expect. When I think of the KKK, I think of the US South and racism against black, but this isn't necessarily true. The KKK has had three incarnations.
The first incarnation was started by six Confederate veterans after the Civil War. This is the group that is depicted in D.W. Griffith classic film, The Birth of a Nation. It was formed in 1865 in Pulaski, Tennessee. It was founded as a secret society for the purpose to restore white supremacy during reconstruction. They claim that they wore hoods, not to hide their identity, but because the group is more important than the individual. So no individuals should stand out over the group. They used violence or threats of violence against the freed men and their supporters. This incarnation was small and fizzled by the mid-1870's.
The second incarnation is the most famous. When you see the KKK portrayed in films, marching or burning crosses, it is usually this one. This group was founded in 1915 outside of Atlanta, Georgia and was inspired by the Griffith film. Griffith was an old college friend of President Wilson. Because of this, unfortunately, The Birth of a Nation was the first film ever to be shone in the White House. It was a new art form at the time and no one had ever seen "historical" events portrayed in this way. Wilson referred to it as "writing history with lightning." The film shows the original Klan as heroes saving the country from non-conciliatory congressmen who sieved control of the US after Lincoln's death and were out to punish the South. It also showed incompetent and immoral freed slaves bumbling about throughout the film (portrayed by white actors in black face). The film is available on Netflix streaming and Hulu Plus if you are ever interested in watching a three hour long right wing propaganda silent film. I recommend it purely as a historical exercise. It was an amazing accomplishment for its time, however misguided.
This second incarnation grew to be much larger than the original by the 1920s. It was very active around the country and became extremely popular in the mid-West states like Illinois, Ohio and particularly in Indiana. Indiana had the largest chapter in the country. The mid-West chapters were far more interested in Catholics than black or Jews. With immigration booming from Germany and Ireland, Catholics were perceived as much more dangerous. For a while, the city of Indianapolis was run by members of the KKK and published the names of Catholic owned businesses to boycott. During prohibition, they took it upon themselves to enforce the laws themselves. They stopped cars and patrolled lover's lanes looking for booze. They were a political force. Klan member, Governor Ed Jackson introduced the "Bone Dry Bill" that made even an empty bottom of liquor illegal. You could be convicted for possessing the mere smell of liquor. This group fizzled as well when the Grand Dragon, David Curtiss Stephenson, was arrested for the rape and murder of a female state employee.
The recent Klan started back up again in the 1960s in response to the civil rights movement by many of the older members from the 1920s. This is the group that attacked the Civil Rights workers throughout the 60s. Apparently, over 150 chapters still exist in the US today but have little impact. I assume their membership is growing now that we have a black president. They are considered a terrorist group now. They consider themselves Christians in the same way that Al-Qaeda considers themselves Muslim; anyone who knows much about either of these religions knows how wrong this is. Gays and Hispanics are among their popular targets now. Just because you don't hear a lot about them doesn't mean that they are not around. No matter what era you live in, there will always be a dangerous radical element.