Two men attacked the ancient monument of Stonehenge with a hammer and chipped off a piece of stone the size of a large coin, a conservation group said Thursday.
Two men hacked the piece from the Heel Stone — the central megalith at the ancient site — last week, English Heritage spokeswoman Debbie Holden said. They were spotted by security guards but escaped by jumping over a fence and driving off.
Wiltshire police are investigating the incident at the UNESCO World Heritage Site located 90 miles (145 kilometers) west of London.
"The damage is very, very slight because security guards spotted them straight away, but the whole thing is still upsetting," said Holden. "This kind of thing has not happened for decades."
The mysterious Stonehenge site is one of Britain's best known and least understood landmarks.
It has become popular with Druids, neo-Pagans and new Agers who attach mystical significance to the strangely shaped stones. There is still great debate about the actual purpose of the site.