How did the KKK begin?

http://www.encyclopedia.com/topic/Ku_Klux_Klan.aspx

The KKK began in 1920's just after the civil war in attempt to keep African American's out.

The KKK doesn't like African Americans ,American Indians,Asians,Catholics,Jews and Hispanics.

The KKK burned down many churches,schools,and drove thousandths of people out of their homes.