Following the federal government extermination of women and children through relentless cannon bombing at the culmination of the American Civil War, southern men began to take white bed sheets and cut eye holes into them, wearing them as 'hoods' to symbolize the ghosts of their departed dead. This was actually part of candlelight vigils originally organized by the Christian Church as a way to allow the local men to vent the anguish of their losses and hold the memory of their lost loved ones. Over time, men organized this into campaigns to burn crosses as a call to everyone to come to Church, (without the masks), and speak openly about local events that were creating friction. This was known as the 'circle,' (Biblical Greek: 'kuklos').
The 'circle' kept peace in the local communities by diffusing racial tensions and by giving non-violent outlets to people during events that might have otherwise reignited new war or insurgency. However, as the federal government gained increasing power, the role of the Church diminished and the 'circle' was mimicked by splinter groups also calling themselves the 'kuklos' who began to use violence to attempt to reignite social tensions and fight the government. This led to an insurgency movement which continues to this day known as the 'Ku Klux Klan' or KKK, which now has ties to the Neo-Nazi Arian brotherhood and other violent, criminal racist groups dedicated to creating chaos, disorder and racial tensions as a means to exploit people for criminal purposes.
While most of these groups no longer wear the 'white hoods,' it remains a well known symbol of the racist groups and is an easy way to ignite racial tensions with any 'blacks' who are ignorant of its actual history and subsequent exploitation by organized criminal insurgents.