What is the KKK famous for doing?

The Ku Klux Klan are well known in America for the racist acts that white Americans did to the Black Americans, because they would track down these people and torture them then eventually kill them because the white Americans believed that they were more superior than the black Americans so they did this to try and prove this point. Additionally, they harassed what they called white sympathizers.

On my own behalf its just a bunch of murderous idiots that didn't have anything better to do }=(