What was the main goal of groups like the ku klux klan?

The KKK was a group about white supremacy, they believed that someone who was white was more superior than any other race. Most members wore a white cape like things (I'm sorry I don't know how to describe) and their leader would wear red. (kinda like the smurfs and the papa smurf) Basically, they favoured the time before the civil war when black people didn't have any rights and were slaves. Throughout the years there have been three groups known as the KKK (Ku Klux Klan) One I think was during the 50's than one in the 70's and I think one started again in the 90's.