Mysterious messages that are only visible at night have been found at an ancient British religious site.

The incredible find suggests our Stone Age ancestors left behind hidden carvings designed to be viewed in the darkness.

However, we don’t yet know what these messages symbolize and why they were carved on the rocks.

Archaeologists led by Dr. Andy Jones of the Cornwall Archaeological Unit found 105 engravings on an axe-shaped stone called a “quoit” which lies on Hendraburnick Down, near Davidstow.

The site appears to have been used during the late Neolithic era, which is regarded as the end of the Stone Age, as well as the early Bronze Age, around 4,000 to 6,000 years ago.

It was used for strange rituals involving the “smashing” of quartz blocks

“During the field work it became apparent that the rock art was far more extensive than had first been thought, and that it was most evident when viewed in low sunlight from the southeast or by moonlight,” the academics wrote in the journal “Time and Mind.”

“It is suggested that the smashed vein quartz may have been used during night-time rituals.”

Modal TriggerThe marking on the bottom of the Hendraburnick Quoit are best viewed at night.Thomas Goskar

“Photogrammetric recording [making detailed measurements using a series of photos] revealed the site to be the most decorated stone in southern Britain and suggests that rather than being pre-planned, the art accreted over time.”

Ancient cultures often associated darkness with “the supernatural and the heightening of senses,” meaning that Hendraburnick Quoit could have played host to strange pagan religious rites.

Jones also found fragments of quartz on the site.

When two pieces of the stone are smashed together, they emit a brief, glowing light.

“The smashed quartz at Hendraburnick could have been used as part of night-time activity on the site in order to ‘release’ the luminescent properties of the quartz around the monument and ‘reveal’ the art in a particular way,” the academics wrote.

“After the ritual, the broken pieces, once they had fallen on the ground, could have effectively formed a wider platform or arc which would have continued to glisten around it in the moonlight, and thereby added to the ‘aura’ of the site.”

Hendraburnick Down is the source of the River Camel, which may have made it a potent spiritual and symbolic site.

The carvings on the fallen stone are known as “cup and ring marks.”

Hendraburnick Quoit has been at the center of a long controversy because some academics believe it is an ancient “long barrow” used to bury the dead.

However, other experts believe the stone is a natural formation while others still believe it was actually a dumping ground used during medieval times.

Jones and his team found a layer of slate beneath the 35,000-pound quoit, indicating it was dragged there from a site down in the river valley and is therefore not a natural formation.

Quoits were found across the ancient world and often feature an indentation surrounded by concentric circles, although the Cornish ones look slightly different.

The markings were mostly located in Northern Europe, but similar patterns have also been spotted as far away as Hawaii and Australia.

Jones told The Telegraph that he expects similar markings to be found at other ancient British sites.

“I think the new marks show that this site was used at night and it is likely that other… sites were as well,” he added.

“Stonehenge does have markings, and I think that many more would be found at sites across the country if people were to look at them in different light.”