The Ku Klux Klan
The Ku Klux Klan, often abbreviated to the "KKK", was an extremist, right-wing organisation that believed in white supremacy and domination over other races. As shown left, they wore white uniform, with white masks and hoods to hide their identity, such as when they committed atrocities, like terrorism, violence and murder.
Throughout history, they have made several appearances, with the first in the South during the 1860s, dying out in the 1870s. However, it is the reappearance of the Ku Klux Klan in the 1920s that worries Jem. He fears that because of Atticus' views on black people, the Ku Klux Klan is after him. Atticus reassures him, telling him basic background information on the Ku Klux.
'They were after you, weren’t they?’ Jem went to him. ‘They wanted to get you, didn’t they?’
Atticus lowered the paper and gazed at Jem. ‘What have you been reading?’ he asked. Then he said gently, ‘No, son, those were our friends.’
‘It wasn’t a – a gang?’ Jem was looking from the corners of his eyes.
Atticus tried to stifle a smile but didn’t make it. ‘No, we don’t have mobs and that nonsense in Maycomb. I’ve never heard of a gang in Maycomb.’
‘Ku Klux got after some Catholics one time.’
‘Never heard of any Catholics in Maycomb either,’ said Atticus, ‘you’re confusing that with something else. Way back about nineteen-twenty there was a Klan, but it was a political organization more than anything. Besides, they couldn’t find anybody to scare.'
...
'The Ku Klux's gone,' said Atticus. 'It'll never come back.'
This last remark of Atticus' is rather ironic, as once again, after the end of World War II, the Ku Klux Klan return. Ironic too is the fact that later in the chapter, smaller scale Ku Klux Clan-like behaviour appears outside the Maycomb Jail, thirsting for Tom Robinson's death.