ELBERTON, Ga. — Part of a mysterious Georgia monument was destroyed by an explosive device overnight, leading to an active police investigation in Elberton, according to the Georgia Bureau of Investigation.

The Georgia Guidestones have since been demolished, the Georgia Bureau of Investigation said Wednesday night.

The Georgia Guidestones were a 19-foot-tall granite monument that served as both a tourist attraction and fodder for conspiracy theories since it was erected by anonymous patrons in 1980.

The monument's stones are inscribed with what some people interpret as guidelines for future generations and what others see as something more sinister. The monument gets around 20,000 visitors a year.