The Ku Klux Klan (KKK), or just the Klan, is the name of three distinct movements in the United States. They first played a violent role against African Americans in the South during the Reconstruction Era of the 1860s. The second was a very large controversial nationwide organization in the 1920s. The current manifestation consists of numerous small unconnected groups that use the KKK name. They have all emphasized secrecy and distinctive costumes, and all have called for purification of American society, and all are considered right-wing.
The current manifestation is classified as a hate group by the Anti-Defamation League and the Southern Poverty Law Center. It is estimated to have between 5,000 and 8,000 members as of 2012.
The first Ku Klux Klan flourished in the Southern United States in the late 1860s, then died out by the early 1870s. Members made their own white costumes: robes, masks, and conical hats, designed to be outlandish and terrifying, and to hide their identities. The second KKK flourished nationwide in the early and mid-1920s, and adopted a standard white costume (sales of which together with initiation fees financed the movement) and code words as the first Klan, while adding cross burnings and mass parades. The third KKK emerged after World War II and was associated with opposing the Civil Rights Movement and progress among minorities. The second and third incarnations of the Ku Klux Klan made frequent reference to the USA's "Anglo-Saxon" blood, harking back to 19th-century nativism. Though most members of the KKK saw themselves as holding to American values and Christian morality, virtually every Christian denomination officially denounced the Ku Klux Klan.