There is a whiff of sadness amid the chatter, the chink of glasses and the good humour that envelops the small crowd gathered inside Abu Dhabi's Ghaf Art Gallery.
It is a Sunday afternoon in late June and the beginning of a three-day exhibition of photographs by Roy Lengweiler.
Twenty of the Swiss expatriate's black-and-white images of the construction of Sheikh Zayed Bridge adorn the gallery's whitewashed walls, as sunshine dapples the window-blinds and laughter fills this intimate, wood-floored space. There is, nevertheless, a sense of an ending at this otherwise upbeat exhibition opening.
Perhaps this is because it is the time of year when departure is on almost everyone's mind. The school year is about to finish, the summer is drawing in and the next few days will be filled with flight, as many residents beat a retreat from the Emirates, some to spend a few days away on annual leave, others to bid the country goodbye for the final time - their work here done, their lives moving on to their next adventure.
Like many others, Lengweiler will soon take his leave.
He will depart Abu Dhabi next month to head for pastures new, having arrived in the emirate nine years ago. He was one of the first professionals - he is a project manager and engineer - on the site of what would become the Sheikh Zayed Bridge, the third link to connect the mainland and Abu Dhabi island. He was still there when it opened.
Lengweiler is a career bridge-builder who has worked in Europe, Asia and the Middle East. He has, he says, been involved with bigger projects than Zaha Hadid's landmark design, but somehow his working life will almost certainly be defined by this elegant 842-metre sculpture that stretches like a playful ribbon over the Maqta Channel.
That's because, beginning in 2003, he would take a point-and-shoot Canon G10 or an old Olympus OM2 with him to work each day to take a few photographs of the men, the site and the epic endeavour as the structure rose from architect's vision to engineered reality.
"You always have to take pictures on a build such as this," he told me in 2010, "Of problems, of difficulties - they are usually used as details in meetings." Day-by-day, week-by-week he began, almost unconsciously, to piece together what might be the most comprehensive archive of one of the most remarkable construction projects in the emirate's history.
A few weeks before the bridge finally opened, The Review ran an interview with Lengweiler together with a collection of his images. Their publication, in October 2010, was the culmination of a lengthy pursuit. Lengweiler was, it might be said, dragged reluctantly towards centre stage.
He was worried that he might be viewed as some kind of obsessive amateur snapper. "I am an engineer, not a photographer," he would tell me repeatedly.
I did my best to assure him that his pictures of the bridge and the men who built it deserved a wider audience. Somewhere along the line Lengweiler reluctantly caved in to my advances, albeit with the caveat that he wanted "the people to be the story" and not him.
Almost two years later, the people are still the story at Lengweiler's exhibition entitled Sheikh Zayed Bridge - The Human Angle.
Staged with the cooperation of the Swiss Embassy and sponsorship from Presence Switzerland, Lengweiler's exhibition - a succession of portraits of men at work and of the bridge's main arches and crown being hoisted into place like the final piece in an elaborate and enormous three-dimensional jigsaw - was officially opened by Wolfgang Amadeus Bruelhart, the Swiss ambassador to the UAE.
Bruelhart, who describes his compatriot as "a role model" for the 2,000-strong Swiss expatriate population in this country, will also shortly be leaving these shores after four and half years of building commercial bridges and fostering friendship between his home country and the UAE.
The ambassador will fly out of the country tomorrow to take up a post in Berne in the Swiss foreign affairs department as director of the Middle East and North Africa division.
Life in the Emirates has clearly left a strong impression on Bruelhart. He departs with "a caravan of memories" and he leaves the population of Abu Dhabi with a slim volume of English- and Arabic-language poetry bearing the same name.
"I was motivated by this culture to express myself in poetry," he says of the collection, which was published earlier this year in a limited print run of 2,000 copies. "Even though it is hard for me to understand Arabic, the music and poetry inspired me to try to write my memories of four years [in the UAE] in verse."
Bruelhart might well be as fascinated by bridges as by poetry. Certainly they are a recurring theme in his own life.
He was brought up in the Swiss canton of Fribourg, a charming city known for its bridges, old and new, which link the French and German parts of Switzerland. His first diplomatic posting took him to Sarajevo in 1996, the capital of Bosnia and Herzegovina, a country synonymous with the historic Stari Most bridge, a causeway that stood for more than 400 years before its wilful destruction during the Siege of Mostar in November 1993. It has since, of course, risen once more, a faithful restoration of an architectural wonder. He says his time in Bosnia was "tough, but there was hope for a better future".
And that, perhaps, is the point of Lengweiler's exhibition.
The building of a bridge makes a physical link between two previously separate points. More than that, it connects people - those who helped build it, those who rely on it every day to reach their destination.
His photographs talk directly to that sense of hope and that deep-seated bond.
We see it in the faces of the workers atop the bridge's main arch, we understand it in the interdependence of the engineering and architecture of Zaha Hadid's Middle Eastern masterpiece and we grasp it in the extreme conditions we find these migrant workers toiling in: "The bridge is so light, so elegant now," says the photographer, "but a lot of sweat and hard work went into it."
He says that manual work and people remain at the heart of the construction process unlike industrial production, which is now largely mechanised. He wanted simply to document and celebrate that process.
The gallery is abuzz with friends, colleagues and dignitaries responding to and, indeed, enjoying Lengweiler's work. Surely today, of all days, he must consider himself as a photographer rather than an engineer?
No, he replies, steadfast as ever.
And how does he feel about the bridge now?
"It is finished and it is open, but for me the bridge is closed. Now the photographs are much closer to me [than the bridge], because they still show what was there and how it was made. And since I am not an architect, I am engineer, I am only interested in how things are built and who is building them."
And then, as I am thinking that Lengweiler is ever the engineer, never the photographer, he replays a conversation and a notion he first raised a long time ago.
"I still hope to publish a book of my photographs one day, so I think the project will be with me for a while yet."
The creative returns, just as the Swiss engineer prepares to depart.
Nick March is editor of The Review.