Task: Text Categorization
Input (English): Members of this organization identify one another by asking ""AYAK"" and replying ""AKIA. "" Revived in 1915 by William Simmons, this ""invisible empire"" was significantly weakened after Congress passed the Force Bill in 1871. In its heyday, it intimidated people by burning crosses near their homes. Led by a Grand Wizard, this organization sprang up to attack freed slaves after the Civil War. For 10 points, name this American terrorist organization whose members wear white robes and whose name is often abbreviated to the KKK.
Output (English): History