Why did New Zealand engineer Andrea Bald and her 13-year-old son Levi make the round-trip to travel the Antrim Coast Road?
It's the best-known road in Northern Ireland and it frequently features in lists of the world's top 10 scenic drives. But the spectacular Antrim Coast Road is still something of a mystery to the thousands of motorists and tourists who use it every day without a second thought about how it got there.
But now the long and winding road from Larne to Cushendall is featured in a new three-part documentary series on BBC Northern Ireland which tells the remarkable story of how that magnificent part of the A2 was built and how it put an entire community in the Glens of Antrim on the road to a brand new life.
And for New Zealander Andrea Bald the journey along the coast really was a momentous and breathtaking one as for the first time she got to see the road that her great-great-great grandfather had pioneered a century-and-a-half earlier.
William Bald, a resourceful and far-sighted Scot, was the civil engineer who designed and oversaw the construction of the road, but who has been largely forgotten in his adopted homeland.
So much so that no portraits or statues of the unsung hero have ever been found - scant reward for an innovator whose project literally was a ground-breaker as he blasted away towering limestone cliffs to use the fallen debris as the bedrock of his new coast-hugging road.
The only tribute is a small and easy-to-miss plaque, which was unveiled at the side of the road in the Seventies, recognising the "blood, sweat and tears" which had been shed by Bald and "the men of the Glynnes" for the convenience of successive generations of local people and visitors.
The TV series called Shaping the Coast tells how Bald drove forward with one of the biggest civil engineering projects ever carried out in Ireland after his plans were initially dismissed as hair-brained.
Rival designers had favoured the construction of a complicated series of inland roads and bridges to bring the people of the Glens in from the Ulster cold after decades when it had been easier for them to sail across the North Channel to the home of their forefathers in Scotland to conduct their trade rather than attempt to do business in Belfast or Ballymena.
The people of the ancient kingdom of Dalriada in east Antrim and the west of Scotland were, and still are, inextricably linked by their birthrights, but in the 1800s they were a people apart and the Glens were a place apart as the paths over the area's mountains leading to and from them were dangerous at the best of times and impassable at the worst.
To make the Glens more accessible to their fellow Ulster folk, the Commissioners of Pub
Works in Ireland came up with a grandiose notion to construct a new route in and out of the remote area, which it had been acknowledged were cut off "from any reasonable communication by the badness of the roads over mountains and steep slopes".
The idea was one thing, but making it a reality was quite another. The challenging geography of the Antrim coast, with its dramatic cliffs, its hills and expansive valleys, didn't exactly lend itself to road-building, which was never easy in the 19th century - even in the more welcoming terrain of other parts of Ireland.
But Bald was undaunted. He'd been working in Ireland since 1809, when he came to Co Mayo to conduct an ordnance survey before becoming an engineer and designing parts of Drogheda harbour and a suspension bridge over Kenmare Sound in Co Kerry.
He confidently told the Commissioners that he would overcome the obstacles presented by Antrim's coastal headlands jutting out into the Irish Sea by blowing them away with explosives and using the fallen limestone as the foundations for his ambitious new road.
The Commissioners gave him a budget of £25,000 for the coast road in 1832 and weren't best pleased when he ran £12,000 over budget, but he completed the massive task in 10 years.
Even modern-day engineers reflect on Bald's achievements with awe.
David Orr, who was a maintenance engineer for east Antrim for many years, told the programme-makers from Paper Owl Films that he had a deep admiration for Bald, who was born in Burntisland in Fife and was apprenticed as a cartographer.
David said that, in 2016, it would take millions of pounds to build a similar road to Bald's bold construction. But David didn't believe a project like it would even be an environmental runner in an area of outstanding beauty like the Antrim coast, where nature-lovers would also be expected to oppose such a road, because of the impact it would have on the cycle of wildlife.
Another expert contributor to Shaping the Coast, Clive Robinson, is currently employed on the upkeep of the road to protect it from everything that nature can throw at it - particularly from the pounding of unrelentingly powerful waves.
He says: "We are custodians of the coast road and we are trying to keep it safe, reliable and enjoyable for everybody who comes from far and near to use it."
He adds that the road and its sturdy defences - called "revetments" - had saved the coastline from the sea. "Can you imagine if this road hadn't been built here, how many acres of land we'd have lost to coastal erosion?"
He adds that the longevity of the 170-year-old road was way beyond the 100-year design life of any structures which would be built nowadays.
"It has stood the test of time," he says, as he surveys the rock faces above the road for any erosion caused by hard winters and heavy rain, which could cause chippings and fragments to fall on cars below, though fine-meshed netting alleviates potential risks.
Clive describes the planning and the construction of the road by Bald and his workers as "mind-boggling".
He adds: "From an engineering perspective, some of the features you see are very, very innovative, whenever you think this was in the mid-1800s."
Andrea Bald, who is an engineer herself, was clearly happy that her 11,000-mile trek from her New Zealand home to Northern Ireland was worth it.
David Orr filled in a few, but only a few, gaps in her family's knowledge about William Bald, whom he called the "brains of the operation", who'd supervised the construction of the coast road from start to finish using only the resources blasted from the Antrim landscape.
However, underlining just how little is still on record about Bald or his Antrim coast mission, no one was able to answer Andrea's questions about how many men were employed on the building of the road.
She also couldn't find out if any workers had been killed, though hand-me-down stories talk of an unspecified number of fatalities. For Andrea, her visit was a voyage of discovery which she said had exceeded her expectations. And she collected pieces of rock from the coast to take home to her father.
She says: "I knew a little of the road's history, such as when it was built. I'd seen some photos on the internet and I knew its reputation as one of the most spectacular driving routes in the world.
"I discovered that photos really don't do it justice in real life, though. It is really stunning - jigsaw-puzzle picturesque villages, lush farmland and rugged sea cliffs.
"The long views, as you come around a headland and look across to the next village, are just gorgeous."
But Andrea returned home disheartened that she hadn't been able to find out more about William Bald himself.
And it was ironic that she said that her research about the road-builder had reached a "dead end".
She adds: "My dad, Peter, has been researching William Bald on and off since about 2002, when he decided to look into whether his father had been telling the truth, decades ago, when he said my grandfather built the Antrim Coast road.
"It was then (in 2002) that dad found Margaret Storrie's 1960-something paper on the internet and learned that a William Bald had, indeed, built the road.
"In 2007, we confirmed the connection to us by getting a birth certificate from the UK that proved that dad's grandfather, Francis Bald, himself a civil engineer, was the son of Charles, another civil engineer, who was William's eldest son.
"Over the years we've been able to find more and more information, as more records are digitised and put online. We've found bridges, railway designs, maps, reports into water supply, harbour improvements - all manner of civil engineering works - plus quite a lot of family records - marriages, births, baptisms and deaths.
Andrea was accompanied on the trip by her 13-year-old son, Levi Hesseling.
"When he's asked, he tends to say it was 'boring', but it was a great experience for him and I think he really got quite a lot out of it and felt a sense of history and connection, which he probably wouldn't be able to articulate.
"He seems to have picked up a sense of being able to achieve great things by putting in effort and he found it interesting to see the history of Ireland.
"European settlement in New Zealand really only began in about 1800, so it's amazing to us to see things built centuries earlier. We just don't have castles and old inns. He's also a big Game of Thrones fan, so he enjoyed seeing some of the places featured in the series."
The film-makers took Andrea and Levi to the island of Islay off Scotland to meet Storrie, who has been equally frustrated by the lack of clarity about the engineer - though she said she had established that he could be stroppy and impetuous.
However, she described Bald as a very important figure who contributed 30 years of work to the infrastructure of Ireland from piers to railways as well as roads.
But the exasperated author adds: "When you look up William Bald on the internet and you find hundreds of thousands of entries about Prince William's bald patch, it isn't terribly helpful."
Over the three programmes which are narrated by Belfast actor Ian McElhinney who has starred in Game of Thrones, the producers take several fascinating detours from the Antrim Coast road to look at the people of the Glens and their heritage.
They interviewed a raft of local people, including the celebrated artist Hector McDonnell, who grew up in Glenarm Castle, the son of the Earl of Antrim.
The documentary-series also examines the colourful and sometimes bloody history of the Glens and follows their inhabitants as they go about their daily lives and as they socialise in singing groups and set dancing get-togethers in their own homes.
In a later episode the producers talks to people like Davy Smith, a third generation Carnlough fisherman, who has started a new tourism venture in the area, and Adrian Morrow, who manages the Glenarm Castle estate and organises the annual Dalriada festival, which regularly leads to traffic jams ... on the Antrim Coast road.
- Shaping the Coast is a three-part series, starting tomorrow night on BBC Two Northern Ireland at 10pm