8 Intriguing Facts About the Giant’s Causeway

On Northern Ireland's north coast, a striking and mysterious rock formation known as the Giant’s Causeway stands tall. Thousands of hexagonal basalt columns, varying in height, rise from the North Atlantic Ocean and stretch toward a cliff, as though a giant mythical being set them there to bridge the sea. Here are some fascinating details about one of Northern Ireland's most iconic landmarks.

1. The Giant’s Causeway is made up of approximately 40,000 uniquely shaped hexagonal basalt columns.

The unique columns of the Causeway were formed about 60 million years ago when Europe was still connected to North America. As the two continents began to drift apart, rifts appeared, and molten lava from volcanic eruptions flowed through these cracks to create a lava lake, which began to gradually cool. This cooling process caused the lava to contract, forming distinct pillars made up of hexagonal stones.

While it has long been understood that the stones are a natural phenomenon—and not the work of human hands, as it may first appear—the exact conditions needed to form the columns were only uncovered recently. In 2008, Lucas Goehring, a Ph.D. student at the University of Toronto, and his advisor Professor Stephen Morris discovered that 'the slower the cooling process, the larger the resulting columns would be.' Ten years later, Yan Lavallée, Professor of Volcanology at the University of Liverpool, determined the temperature at which the rocks fractured: 1544–1634°F (840–890°C).

2. Legend has it that the Giant’s Causeway was constructed by the giant Finn McCool.

In addition to the scientific explanation for the Causeway’s formation, there’s also the myth that the stones were placed by a giant. Fionn mac Cumhaill, known as Finn McCool or MacCool, was said to have had a rivalry with a Scottish giant named Benandonner. To confront him, Finn built the Causeway across the sea. When he realized Benandonner was much larger than him, Finn fled in fear. Finn’s wife, Oonagh, disguised him as a baby, and when the Scottish giant saw the 'child,' he was tricked into thinking Finn would be enormous. Benandonner then ran back to Scotland, destroying much of the Causeway on his way to prevent being followed.

Though less well-known, there’s also a version of the myth in which Finn is driven by love, not hatred. In this tale, Finn builds the stepping stones to reach a Scottish maiden he’s in love with, but by the time he finishes, he’s so weary that he dies in her embrace.

3. The Giant’s Causeway began to gain recognition outside of Ireland in 1693.

In 1693, Sir Richard Bulkeley, an Irish politician and fellow at Trinity College, Dublin, presented a talk about the geological marvel to the Royal Society. By 1739, the site had become a popular tourist destination, as evidenced by Susanna Drury’s watercolor paintings of the Causeway, which further amplified its fame.

By 1836, tourism had grown so popular that the Causeway Hotel was established to accommodate visitors. It became even easier to reach thanks to the opening of the Giant’s Causeway Tramway in 1883, which connected the town of Portrush to the Causeway.

In 1986, the site was granted official UNESCO World Heritage status. That same year, the National Trust—who had managed the Causeway since 1961—opened a visitor’s center at the location; however, it tragically burned down in 2000, and a new center wasn’t constructed until 2012.

4. In the past, tourists could actually purchase stones from the Giant’s Causeway.

Before The National Trust took control and safeguarded the area, commercial activity was rampant at the Causeway, with parts of it being literally sold to tourists. Scottish writer Leitch Ritchie, who visited the iconic Northern Irish site in the 1830s, reported that 'more than a dozen men and boys follow you through the whole adventure, in spite of your expostulations, to offer boxes of mineralogical specimens.'

In 2010, seven large stones, allegedly from the Causeway, were sold at auction for nearly £20,000 (just over $24,000). While there was some skepticism about the stones' authenticity, some locals have real Causeway stones in their gardens.

5. The area is home to other uniquely shaped rocks.

In addition to the thousands of hexagonal stones, the Causeway coast features several distinctive rocks. Among the most famous are 'the camel' and 'the giant’s boot,' both linked to the legend of Finn McCool. The camel, lying at the base of the cliffs, is said to have been the only creature capable of carrying Finn, while the enormous boot, which is roughly size 9 (around size 94 or 95 in U.S. men’s shoes), was lost by Finn while fleeing from Benandonner in a Cinderella-style escape.

But the area offers even more fascinating geological wonders. Above the Causeway, you’ll find the towering chimney stacks, while along the cliff face are columns resembling organ pipes and a giant harp. Visitors can also spot the human-sized Wishing Chair, a natural throne created by the basalt columns.

6. The cover of Led Zeppelin’s 1973 album *Houses of the Holy* was created using photographs taken at the Giant’s Causeway.

Led Zeppelin’s *Houses of the Holy* album cover features naked blonde children crawling over stones in an otherworldly landscape. In *Bill and Ted’s Excellent Adventure* (1989), Bill and Ted describe 470 BCE as 'a time when much of the world looked like the cover of the Led Zeppelin album *Houses of the Holy*.' While they are referring to Ancient Greece, the iconic image was actually taken at the Giant’s Causeway.

Aubrey Powell of the design firm Hipgnosis designed the cover, drawing inspiration from Arthur C. Clarke’s sci-fi novel *Childhood’s End* (1953). Although it appears to be one single image, it’s a blend of 30 separate photos. Only two children were used for the shoot—Stefan Gates, who later became a TV presenter, and his sister Samantha. 'We were naked in a lot of the modeling shoots we did, and no one thought anything of it back then. You probably couldn’t get away with that now,' Samantha once remarked.

The ever-present Irish rain forced Powell to abandon his original plan of shooting in color with the children painted in gold and silver. 'Because I shot in black and white and it was a gray day, the children turned out very white,' Powell explained. A fortunate mistake led to the iconic cover: 'When we hand-tinted it, the airbrush artist accidentally gave them a purple hue. When I first saw it, I thought, 'Oh, my God.' But then I looked at it again and realized it had an otherworldly quality. So, we kept it that way.'

7. The Giant’s Causeway has appeared in several films.

The stunning and unique landscape of the Giant’s Causeway has made it a sought-after filming location, though it is notably missing from the list of *Game of Thrones* filming spots in Northern Ireland. The Causeway served as a Transylvanian mountain in *Dracula Untold* (2014), as part of the Minotaur’s labyrinth in *Your Highness* (2011), and made an appearance as itself in *Hellboy II: The Golden Army* (2008).

8. Similar rock formations exist around the globe—and even on Mars.

While the Giant’s Causeway is the most well-known example of columnar jointing, there are other similar formations around the world. Just a short distance across the sea on Scotland's Isle of Staffa, you'll find Fingal’s Cave, a sea cave formed from hexagonal basalt columns created by the same volcanic lava flow that formed the Causeway.

Other notable examples include Wyoming’s Devil’s Tower, a striking isolated hill with pillars rising 867 feet (265 meters) into the air, and High Island Reservoir in Hong Kong, known for its unique pillars made from rhyolitic tuff, a volcanic rock that doesn't typically form hexagonal columns.

In 2007, lava columns were even discovered and photographed on Mars—demonstrating that volcanic activity has played a significant role on both Earth and the Red Planet.