Attracting legions of tourists every year, it is one of the world’s most intriguing rock formations.
The Giant’s Causeway, on the northern coast of Northern Ireland, was formed around 60million years ago.
But now, the volcanic formation is under threat – thanks to a scourge of tourists jamming coins between its stones, often for reasons of love or luck.
The National Trust, which cares for the feature, has issued a plea to visitors to stop the damaging trend, which is similar to the fixing of padlocks to monuments such as Paris’s Pont des Arts bridge.
When the coins rust they expand to three times their original thickness and put ‘huge pressure’ on the surrounding rock, causing it to ‘crumble’, Trust expert Dr Cliff Henry said.
The bill to remove the coins, which are also leaving reddish rust stains behind, is expected to be more than £30,000.
Dr Henry, the National Trust’s nature engagement officer at the Causeway, said: ‘We know that visitors really love and cherish the Giant’s Causeway, and many form deep personal connections to this special landscape.
‘We know some may want to leave a token of their visit, but the coins are causing damage and we are urging people to stop the practice and to leave no trace so this natural wonder remains special for future generations.’
The National Trust has issued a plea to tourists to stop jamming coins between the cracks of the Giant’s Causeway in Northern Ireland. Above: Some of the coins recovered from the historic formation
The bill to remove the coins, which are also leaving reddish rust stains behind, is expected to be more than £30,000
A report by the British Geological Survey found that the coins are having a detrimental effect on the basalt rock, both aesthetically and physically.
Dr Henry added: ‘The report has found that fracturing and disintegration of the basalt rock adjacent to joints and cracks into which coins have been inserted is the result of the «expansive delamination of the coins upon oxidation».
‘In other words, the coins are rusting, and expanding to three times their original thickness, which puts huge pressure on the surrounding rock causing it to crumble.
‘Unsightly streaks of copper, nickel and iron oxides are also staining the stones where the coins are corroding.’
The coins left behind are mostly from UK visitors but are also from Europe, the USA, Far East and elsewhere.
In 10 test locations, the National Trust employed specialists to remove as many coins as possible without causing further damage.
The trial was successful so it is hoped all the remaining coins will also soon be removed.
Since 1992, ‘copper’ coins in the UK have had a steel core with just a thin layer of copper on the outside.
The Giant’s Causeway, on the northern coast of Northern Ireland, was formed around 60million years ago
The coins are damaging the Causeway when they expand and then rust
A report by the British Geological Survey found that the coins are having a detrimental effect on the basalt rock, both aesthetically and physically
Two rusted coins seen after being recovered from a gap in the Causeway
In 10 test locations, the National Trust employed specialists to remove as many coins as possible without causing further damage
Coins jammed between rocks at the Giant’s Causeway
The Giant’s Causeway was created by an outpouring of basalt lava 60million years ago, when the North Atlantic was opening up
Five, 10 and 20 pence pieces are nickel-plated steel. When the coin begins to corrode, the steel corrodes more quickly than the other metals and so separates.
The delamination causes the surrounding basalt to ‘flake’, Dr Henry said.
‘The coins here also have accelerated corrosion because they are often soaked in saltwater spray and the mixture of metals means they break down faster,’ he added.
‘We protect and care for places so people and nature can thrive.
‘We are appealing to visitors to help us protect the World Heritage Site by stopping the practice of inserting coins into the Causeway stones.’
The Giant’s Causeway was created by an outpouring of basalt lava 60million years ago, when the North Atlantic was opening up.
Local legend gives the more exciting explanation that mythical giant Finn McCool created a causeway to get across the Irish Sea to fight his rival, the Scottish bruiser Benandonner.
But his rival then tore up most of the causeway to prevent Finn from getting to Scotland.
Another legend says that Finn built the causeway so he could meet a Scottish maid he was enamoured with.
