Conservation workers at the Giant's Causeway in Northern Ireland have extracted more than 10,000 coins wedged into the site's ancient basalt columns by tourists.
The National Trust, the UK heritage conservation charity responsible for managing Northern Ireland's only UNESCO World Heritage Site, executed the complex clearance operation after discovering that corroding metal was inflicting severe physical and chemical damage on the rock formations.
According to a report published by the BBC, specialist teams recovered more than 20 kilograms of metal currency that visitors had driven into narrow rock crevices as good luck tokens over many years.
The custom of inserting coins into small gaps between the rocks at the famous County Antrim landmark had been occurring for years, but conservation authorities reported a sharp escalation in the practice over the past decade.
Rather than simply placing coins loosely inside open crevices, many visitors actively hammered the metal deep into narrow gaps between the basalt pillars using loose stones gathered from the surrounding shoreline.
Damage to basalt columns
Concerns regarding the practice intensified following a detailed study by the Geological Survey of Northern Ireland, the public body responsible for providing geological advice and mapping across the region.
The survey issued a formal report recommending the complete removal of all embedded coins, warning that metal left inside the rock threatened the natural monument through both chemical reaction and mechanical stress.
Over time, coins exposed to coastal weather, rain, and salty sea air undergo corrosion, producing rust-coloured oxidation stains that discolour the dark, fine-grained basalt rock.
The physical impact proved equally damaging to the ancient geological structures, as coins forced tightly into narrow openings exert continuous outward pressure against the stone.
As the embedded metal deteriorates and expands due to oxidation, the expanding volume increases pressure against the sides of the crevices and basalt columns, threatening long-term structural integrity.
Furthermore, the physical action of tourists using heavy stones to strike coins into place caused direct mechanical damage, widening natural rock fissures and causing small rock falls and surface detachments.
Dr Cliff Henry, the nature engagement manager for the National Trust, stated that completing the clearance brought great relief to conservation staff because the coins had been causing significant damage to the basalt columns.
Removal of embedded coins
The dedicated clearance operation commenced in May last year and developed into a painstaking process requiring immense patience and precision to avoid causing further harm to the delicate rock formations.
To execute the precise extraction work, the National Trust hired stone specialist Nathan Morrow, who had to employ multiple techniques depending on how deeply each individual coin was lodged.
Coins positioned near the outer edges of the basalt crevices could generally be removed quickly using fine tweezers without disturbing the surrounding rock.
However, coins driven deep into extremely tight gaps presented a much tougher challenge, requiring Morrow to use a specialized stone grouting tool to loosen packed debris and ease the metal free.
While accessible coins dislodged almost immediately, the most stubborn pieces required more than 20 minutes of continuous, careful manipulation to extract safely.
In those difficult cases, Morrow had to work each coin back and forth repeatedly until it dislodged, taking care to avoid applying excessive force or leverage against the fragile edges of the basalt.
The cumulative haul of more than 20 kilograms of coins demonstrated how widespread the wish-making habit had become among the hundreds of thousands of tourists visiting the landmark annually.
Volcanic origins and conservation efforts
The Giant's Causeway, located on the wild northern coast of County Antrim, is a natural geological marvel formed millions of years ago by intense volcanic activity rather than human construction.
The site comprises roughly 40,000 interlocking basalt columns created when subterranean molten rock surged through earth fissures, cooled rapidly, and contracted into regular geometric structures that step down into the ocean.
In addition to its scientific importance, the unique basalt landscape inspired centuries of Gaelic folklore, most famously the Irish myth of the giant Finn McCool, also known as Fionn mac Cumhaill.
According to local legend, the giant built the grand stone causeway across the sea to Scotland so he could walk across the water to challenge a rival giant.
To prevent recurring damage to the World Heritage Site, the National Trust has installed clear new signage across the area requesting that visitors refrain from inserting coins into the rock crevices.
The conservation charity is also using its official social media channels to reinforce the educational message and inform the public about the harm caused by coin wedging.
Dr Henry suggested a practical alternative for tourists wishing to leave money as a keepsake or gesture of good luck, encouraging them to place their coins into designated charity donation boxes so their contributions benefit good causes without endangering ancient natural formations.
