A granite monument in the US state of Georgia has been demolished for safety reasons after being damaged in a blast.
An explosion early on Wednesday reduced one of the slabs at the Georgia Guidestones to rubble.
CCTV footage showed a car leaving the scene and authorities are investigating.
Despite being built in 1980, the monument has been nicknamed "America's Stonehenge", a reference to the prehistoric landmark in the UK.
The 19ft-high (5.8m) structure near Elberton, east of Atlanta, was commissioned by a person or a group under the pseudonym RC Christian.
On 22 March 1980, the Georgia Guidestones, weighing 119 tons, were revealed to a crowd of about 100 people.
One crowd member, a local pastor, immediately professed his belief that the stones were built for cult and devil worship because of their similar appearance to Stonehenge.
On each side of the capstone, engraved in four ancient languages - Babylonian cuneiform, Classical Greek, Sanskrit and Egyptian hieroglyphic - were the words: "Let these be guidestones to an Age of Reason."
And written in eight languages - English, Russian, Mandarin Chinese, Arabic, Classical Hebrew, Swahili, Hindi and Spanish - were cryptic instructions for rebuilding society post-Doomsday:
"Maintain humanity under 500,000,000 in perpetual balance with nature; Guide reproduction wisely - improving fitness and diversity; Unite humanity with a living new language; Rule passion - faith - tradition - and all things with tempered reason; Protect people and nations with fair laws and just courts; Let all nations rule internally resolving external disputes in a world court; Avoid petty laws and useless officials; Balance personal rights with social duties; Prize truth - beauty - love - seeking harmony with the infinite; Be not a cancer on the Earth - Leave room for nature - Leave room for nature."
The state tourist website ExploreGeorgia.org says the monument serves "as an astronomical calendar, and every day at noon the sun shines through a narrow hole in the structure and illuminates the day's date on an engraving".
Conspiracy theorists celebrate bombing
Shayan Sardarizadeh, BBC Monitoring
The Georgia Guidestones have long been a focus for conspiracy theories. Some believe the monument to be "Satanic" and a "portal to hell".
It has been linked to the "New World Order" theory, about a purported plot by global elites to rule mankind. In 2008, the monument was defaced with the slogan "death to the New World Order" in red paint.
Claims that the stones contained instructions on depopulating the earth have also circulated online. To support this idea, some have quoted the inscription etched on the stones: "Maintain humanity under 500,000,000 in perpetual balance with nature."
The Covid pandemic and the global vaccination programme gave a new boost to these conspiracies. Kandis Taylor, a losing candidate in Georgia's Republican gubernatorial primary, pledged to destroy the stones as part of her campaign.
News of the monument's demolition has been cheered in some online circles. Conspiracy theorist Alex Jones said he enjoyed the bombing of the stones "at an animal level", but added he would like them to stand as an "evil edifice" exposing depopulation plans.