The Ku Klux Klan (means White Racial Brotherhood) is a notoriously known group-once known as the Kuklux Clan. This group was a "secret" organization that used physical violence such as murder against African Americans and their supporters, as well as victimize and suppress newly freed slaves.
This group was founded by Nathan Bed Forrest, in 1865, at Tennessee, after the war. The Ku Klux Klan is infamous for burning crosses and murdering African Americans daily. This group still somewhat exists in today's society.