The Ku Klux Klan (KKK) is an American white supremacist and reactionary secret society which was first founded in Pulaski, Tennessee in 1865 as a Confederate veterans' organization. The organization took its name from the Greek word "kuklos" (meaning "circle"), seeing itself as a fraternal organization and a secret society. Its members were given fanciful titles such as "klabee" (treasurer), "Imperial Kleagle" (recruiter), and "Imperial Kludd" (chaplain); former Confederate general Nathan Bedford Forrest became their first "Grand Wizard" (head of the organization). Its members wore colorful costumes of robes, masks, and conical hats which made them appear to be ghosts. The first Klan sought to overthrow Republican state governments in the American South, doing so through intimidating or lynching African-American and scalawag (white Republican) voters, or even through assassinating carpetbagger politicians. In 1871, President Ulysses S. Grant passed the Force Act, which enabled him to military suppress the Klan, whose decentralized structure had already weakened it.
In 1915, William Joseph Simmons was inspired by the silent film The Birth of a Nation - which mythologized the Klan as a noble vigilante group - to refound the Klan at Stone Mountain, Georgia. He was also inspired by the movie's portrayal of cross burnings (which were signs used by the medieval Scots to rally soldiers for war), and the rise of the second Klan was heralded by cross burnings on Stone Mountain. Due to the influx of Catholic and Jewish immigrants, the rise of communism, women's suffrage, and the start of Prohibition at the end of a progressive era, the Klan flourished in Protestant communities across the country, supporting nativism, anti-Semitism, anti-Catholicism, and the maintenance of the supremacy of white Anglo-Saxon Protestants in the United States. It sold its members standard white costumes, and it took part in cross burnings and mass parades to intimidate its enemies. By 1925, it had 6,000,000 members, but it declined in the late 1920s due to Grand Wizard D.C. Stephenson's murder of white schoolteacher Madge Oberholtzer, which showed the Klan's hypocrisy. Due to the American public's staunch opposition to Nazism during World War II, the Klan's popularity declined further, and it disbanded in 1944.
In 1946, a third Klan rose in the form of local and isolated groups such as the Loyal White Knights of the Ku Klux Klan, the White Knights of the Ku Klux Klan, and the Imperial Klans of America. It grew in response to the progression of the Civil Rights movement, and its members used violence and murder to suppress its activists, murdering Medgar Evers and carrying out the 16th Street Baptist Church bombing in 1963, murdering three civil rights workers in Mississippi in 1964, and murdering Viola Liuzzo during the Selma to Montgomery marches of 1965, among many other violent acts. However, the FBI began to infiltrate the Klan as a part of its COINTELPRO program, and the Klan would decline from 10,000 members in 1991 to 6,000 in 2016. However, the 2016 presidential election, the rise of the alt-right, and the popularity of right-wing populist Republican presidential candidate Donald Trump led to a spike in hate crimes as the Klan reached a new strength of 15,000 in 2017. The Klan, although splintered, generally adopted neo-Nazi, anti-Islam, and anti-gay rights views as a part of a conservative shift in American society under Trump.