On the north coast of Northern Ireland sits an otherworldly rock formation known as the Giant’s Causeway. There, thousands of hexagonal stone columns of various heights rise out of the North Atlantic Ocean and climb up to the foot of a cliff, as if they had been placed by a massive mythical creature to help him cross the sea. Here are a few facts about one of Northern Ireland’s most popular tourist attractions.
1. The Giant’s Causeway is comprised of around 40,000 hexagonal basalt columns.
The Causeway’s distinctive columns were formed around 60 million years ago, when Europe was still attached to North America. As the landmasses began to separate, rifts were caused and molten lava from volcanic activity flowed through these fissures to create a lava lake, which then began to slowly cool. This cooling process caused the lava to contract and fracture into pillars made up of hexagonal stones.
Although it has long been known that the stones are a natural formation—and not artificially sculpted, as it may initially seem—the exact conditions that were needed to create the columns were only recently identified. In 2008, University of Toronto Ph.D. student Lucas Goehring and his supervisor Professor Stephen Morris found that “the slower the cooling process, the larger the resulting columns would be.” Ten years later, Yan Lavallée, Professor of Volcanology at University of Liverpool, worked out the temperature at which the rocks fractured: 1544–1634°F (840–890°C).
2. According to legend, the Giant’s Causeway was built by the giant Finn McCool.
As well as the scientific explanation of the Causeway’s creation, there is also the myth that the stones were placed by a giant. Fionn mac Cumhaill, anglicized as Finn McCool or MacCool, had a feud with a Scottish giant called Benandonner and built the Causeway across the sea so they could fight. He then realized Benandonner was bigger than him and fled in terror. Finn’s wife, Oonagh, disguised him as a baby, and when the Scot saw the alleged child, he was tricked into thinking Finn would be enormous. He ran back to Scotland, destroying most of the Causeway on his way so he couldn’t be followed.
Although less popular, there is also a myth that Finn was motivated by love, not hate. In this version Finn places the stepping stones to reach the Scottish lass he’s in love with, but is so exhausted by the time he finishes that he dies in her arms.
3. The Giant’s Causeway first gained recognition outside of Ireland in 1693.
In 1693, Sir Richard Bulkeley, an Irish politician and fellow of Trinity College, Dublin, gave a presentation about the geological wonder to the Royal Society. By 1739, the site had become a tourist attraction—as is shown in Susanna Drury’s watercolors of the Causeway—which in turn helped bring the location even more attention.
Tourism was so popular by 1836 that The Causeway Hotel was built to accommodate travelers to the area. It became even more accessible thanks to the Giant’s Causeway Tramway, which opened in 1883 and ran between the town of Portrush and the Causeway.
In 1986 the site was officially given UNESCO World Heritage status. That same year, the National Trust—which has managed the Causeway since 1961—also built a visitor’s center at the site; that burned down in 2000, and a new one wasn’t built until 2012.
4. Tourists used to be able to buy Giant’s Causeway stones.
In the years before The National Trust acquired and protected the area, commercialism was rampant at the Causeway—to the extent that parts of it were literally sold to tourists. Scottish writer Leitch Ritchie visited the iconic Northern Irish landmark in the 1830s and 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 that were said to have been from the Causeway sold at auction for nearly £20,000 (a little over $24,000). Although there was doubt about the authenticity of the stones, there are locals who have genuine Causeway stones in their gardens.
5. There are other oddly shaped rocks scattered across the area.
Along with the thousands upon thousands of hexagonal stones to see, there are also a number of uniquely shaped rocks dotted around the Causeway coast. Two of the most well-known are the camel and the giant’s boot—both of which are tied to the legend of Finn McCool. The camel that lies at the bottom of the cliffs is said to have been the only beast capable of carrying Finn, while the massive boot—allegedly size 93.5 (around a size 94 or 95 in U.S. men’s measurements)—was lost by Finn as he fled Cinderella-style from Benandonner.
Those aren’t the only intriguing geological features in the area. Perched above the Causeway are the chimney stacks and set into the cliff-face are columns that resemble organ pipes and a giant harp. Visitors can also seek out the human-sized Wishing Chair, which is a natural throne created by the basalt columns.
6. The cover of Led Zeppelin’s 1973 album Houses of the Holy was created with photos taken at the Giant’s Causeway.
Led Zeppelin’s Houses of the Holy album cover depicts eerily similar naked blonde children crawling over stones in a bizarre landscape. Bill and Ted in Bill and Ted’s Excellent Adventure (1989) describe 470 BCE as “a time when much of the world looked like the cover of the Led Zeppelin album Houses of the Holy.” They’re referring to Ancient Greece, but the cover was actually shot at the Giant’s Causeway.
Aubrey Powell, of the design firm Hipgnosis, designed the cover and was initially inspired by Arthur C. Clarke’s sci-fi novel Childhood’s End (1953). Although it looks like one image, it’s actually a composite of 30 different photographs. Only two children were needed for the shoot—Stefan Gates, who went on to become a TV presenter, and his sister Samantha. “We were naked in a lot of the modelling shoots we did, nothing was thought of it back then. You probably couldn’t get away with that now,” Samantha once commented.
The relentlessly rainy Irish weather forced Powell to change his original plan of shooting in color and for the children to be 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 mistake then led to the iconic cover: “So when we hand-tinted it, the airbrush artist, by accident, put a kind of purple tinge onto them. When I first saw it, I said, ‘Oh, my God.’ Then we looked at it, and I said, ‘Hang on a minute—this has an otherworldly quality.’ So we left it as it was.”
7. The Giant’s Causeway has been featured in multiple movies.
The unusual beauty of the Giant’s Causeway makes it a perfect filming location—although it is noticeably absent from the list of Game of Thrones filming locations throughout Northern Ireland. The Causeway is featured as a Transylvanian mountain in Dracula Untold (2014), as part of the Minotaur’s maze in Your Highness (2011), and as itself in Hellboy II: The Golden Army (2008).
8. Similar rock formations can be found around the world—and even on Mars.
The Giant’s Causeway is the most famous example of columnar jointing, but there are other similar formations located around the world. Just a hop across the sea on the Scottish Isle of Staffa is Fingal’s Cave, a sea cave of hexagonal rocks created by the same lava flow as the Causeway.
Other examples include the Devil’s Tower in Wyoming, which is a dramatic isolated hill formed of pillars stretching 867 feet (265 meters) into the air, and High Island Reservoir in Hong Kong, which is unique because the pillars are made of rhyolitic tuff, a viscous volcanic rock that does not usually form hexagonal columns.
In 2007, lava columns were even spotted and photographed on Mars—like Earth, the surface of the Red Planet owes a lot to volcanic activity.