The Ku Klux Klan (KKK) is a white supremacist hate group that originated in the United States after the Civil War. The KKK used violence and intimidation tactics like burning crosses and lynchings to terrorize African Americans and other minority groups. In the 1920s, the KKK grew rapidly and had over 6 million members nationwide as it promoted racist, anti-Semitic, anti-Catholic, and anti-immigrant ideologies. The KKK often operated secretly at night wearing white costumes with masks to hide their identities while carrying out attacks and violent crimes against their targets.