Giant's Causeway visitors urged not to leave 'damaging' mementos in historic rock formation

28 May 2025, 10:19 | Updated: 28 May 2025, 10:35

The Giant's Causeway faces 'rapid erosion' from tourists jamming coins into gaps on the 60-million-year-old rocks.

The rock formation, in Northern Ireland, sees hundreds of thousands of tourists and locals every year.

Some jam coins between the famous rock columns, but the site's caretakers, the National Trust, is now begging tourists to stop.

The worst rock formation affected are the basalt columns that make up The Loom, a 10 ft high leaning towers of rock.

Dr Cliff Henry, a nature engagement officer with the National Trust, said: "People see others put coins in, so they copycat, they take a coin out of their pocket and they might take a stone off the ground to hammer the coin in, but they might miss and chip the stone itself so that's doing damage."

The columns where the coins have been interest are a lighter colour than the iconic black basalt. The coins left a red-brown over the rock face.

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He added: "Once the coin is in there it starts to rust and due to the atmosphere here it rusts at an accelerated level.

"The coin then expands and that's putting pressure on the joint near the edge so we have seen on a number of places here that the corners have popped off.

"And the rusting metal in there is starting to leach. The iron and nickel and copper is leaching out over the rocks and it looks unsightly."

He pointed to a report by The British Geological Survey that concludes the coins wedged into the joints and cracks in the rock are having a detrimental impact on the basalt rock of the Giant’s Causeway, both aesthetically and physically.

He concluded: "On a geological timescale, this is very rapid erosion."

Dr Kirstin Lemon from The Geological Survey of Northern Ireland told the BBC: "The advice of the Geological Survey to the National Trust is to see if we can remove as many of those coins as we can.

"By removing them, it means we're stopping any further physical impact on the site itself. We're also stopping that chemical impact as well."

Signs will be put up and visitors are already warned not to leave the coins by tour guides at the famous site.

"It's an icon for Northern Ireland - if we can't look after this, what's the hope for the rest of the country?," said Dr Henry.

"We really need to be looking after the causeway as best we can."

The Giant's Causeway received about 684,000 visits last year.

While geologists will say that the causeway was created by an outpouring of Basalt lava 60 million years ago around the time the North Atlantic was opening up, there are also legends that it was formed by an Irish giant Finn McCool.

The National Trust protects and cares for more than 40,000 columns at the Giant’s Causeway, which is Northern Ireland’s first Unesco World Heritage Site and also benefits from a number of other important designations.