It started during the rebuilding at the end of the Civil War, the Klan quickly assembled as an alert group to threaten the Southern blacks -- and any other whites who would help them -- and to stop them from enjoying basic civil rights. Strange titles (like Imperial Wizard and Exalted Cyclops), hooded costumes, violent "night rides" and the idea that the group included an "invisible empire" conferred a air of mystery that only added to the Klan's popularity. Execution, tar-and-featherings, rape and other violent attacks on those challenging white supremacy became a trademark of the Klan.
After a short but violent period, the "first era" Klan breaks up after Jim Crow laws secured the power of Southern whites. But the Klan enjoyed a huge renewal in the 1920s when it opposed (mainly Catholic and Jewish) immigration. By 1925, when its followers staged a huge Washington, D.C., march, the Klan had as many as 5 million members and, in some states, considerable political power. But a series of sex scandals, internal battles over power and newspaper exposés quickly reduced its influence.
The Klan arose a third time during the 1960s to be in opposition to the civil rights movement and to protect segregation in the face of adverse court rulings. The Klan's bombings, murders and other attacks took a great many lives including, among others, four young girls killed while preparing for services at the 16th Street Baptist Church in Birmingham, Ala.
Since the 1970s the Klan has been very much damaged by internal conflicts, court cases, a apparently never-ending chain of splits and government penetration. While some groups have preserved an openly racist and rebellious approach, others have tried to enter the normal, covering their racism as a simple "civil rights for whites."
This is the Ku Klux Klan flag
