On Thanksgiving evening in 1915, William J. Simmons gathered fifteen men and ascended the windy summit of Georgia’s imposing Stone Mountain, just outside of Atlanta. Atop the mountain, they built an altar of sixteen boulders, upon which they placed an American flag, a copy of the Holy Bible, and an unsheathed sword.

Then, standing in the moonlight, they raised an enormous wooden cross and set it alight.

With “the angels” watching over them “shout[ing] hosannas,” Simmons and his men pronounced the Ku Klux Klan newly reborn, and inaugurated a new and terrible phase for an organization that had lain dormant for several decades. This was the beginning, they declared, of a new imperial empire.