Early one morning last summer, I stood inside a museum in Antwerp and watched as a painting was hung on the wall. When I walked in, the gallery was empty. To one side, there was a crate about a metre square. Royal blue, it was unmarked apart from a code number and a yellow stencilled sign reading “Lato da Aprire / Open this Side”. Although its home is nominally Florence, the painting inside was a seasoned traveller: it had arrived the night before from Sicily, by road and under armed guard. The box looked entirely unremarkable. That was the point, I was told.

Abruptly, there was a commotion: the curator of the exhibition, a visiting curator, a translator, an expert in Renaissance art, plus a clutch of hangers-on, burst through the doors. Two art handlers wearing gloves and sober expressions strode over to a table; on it, pliers, tape measures, and an electric screwdriver had been placed with a precision that would not have been out of place in an operating theatre.

While the group noisily exchanged paperwork and air kisses, the visiting curator – who had accompanied the painting on its journey – gave the handlers sotto voce instructions. The crate was laid flat on the floor, its lid unscrewed and the foam packing lifted out. The screws that would attach the painting to the wall were held up for inspection; she gave a curt nod of assent. The only sound was the squeak of one handler’s trainers on the floor.

As the final layer of foam came off, there was a flash of gold reflected on the gallery ceiling. Craning my neck, I glimpsed the edge of Caravaggio’s Boy Bitten By a Lizard, one of the artist’s most sensational early masterworks – a young face contorted in shock and pain, body twisted, eyes dark and cheeks flushed. Gently, the handlers placed the painting, one of two authenticated versions, on the table. There was a scattering of applause. It was though a celebrity had materialised in our midst.

Even if you are an obsessive gallery-goer, it’s possible you haven’t put much thought into how the works on the wall came to be there. The art world prefers it this way: what happens behind the signs reading “No Entry: Installation in Progress” remains a ferociously guarded secret. The only hint that this Song dynasty bronze has arrived from that private collection in Taiwan, for example, is a discreet credit on the wall. It may be that, absorbed in our face-to-face encounter with the artwork – what Walter Benjamin described as its “aura” – many of us prefer not to gaze too deeply into that mystery.

Facebook Twitter Pinterest Edvard Munch’s The Scream being hung at the British Museum in London this week. Photograph: Kirsty O’Connor/PA

Yet the mechanisms required to get that bronze from Taipei to St Ives – loan agreements, insurance, packing, couriering, shipping, handling, installation – are delicate, expensive and complex. Behind every exhibition is an intricate logistical web that reaches across the globe.

Institutions are under huge pressure to share collections, both in the UK and internationally. Missed Frida Kahlo at the V&A? It has recently opened at Brooklyn Museum, just as the Metropolitan Museum’s 2017 exhibition of early Diane Arbus has come to London. The British Museum’s A History of the World in 100 Objects is shortly to arrive in Hong Kong, by way of Abu Dhabi, Taiwan, Japan, Australia and China. It has been on the road since 2016. Many museums now rely on blockbuster exhibitions to drive visitor numbers; often, the only way of paying for these is to partner with another institution and send the show on tour.

The demands of creating large shows populated with star loans, and the logistics required to make them come together, are intense. “It has become a sort of arms race,” said one curator I spoke to, with a trace of a sigh.

A hyperactive art market creates a momentum all its own. According to the most recent analysis, global art sales total nearly $68bn (£52bn) annually, a 10% increase since 2008, with some 40m transactions made last year alone. Vast quantities of art are continually being shifted from auction houses to purchasers to dealers and back again, especially in the fast-expanding Asian markets. Two decades ago, there were around 55 major commercial art fairs; now, there are more than 260.

The end result is that more art than ever, worth more money than ever, is travelling more than ever. Fine-art shipping is expensive, specialised and technically challenging work. Old masters are fragile, but some contemporary sculptures are so friable – or so poorly fabricated – that moving them anywhere is a major risk. And there is the added pressure of handling artefacts that are almost immeasurably culturally important.

There is perhaps another paradox here, too: desperate for a glimpse of genuine “aura” in an era of digital reproduction, we crave that once-in-a-lifetime opportunity to see those real Cézannes sharing a real wall, and stand in their presence, as the artist stood. But although the real value of a work of art lies in its being seen, simply putting it on display – let alone making it travel – is guaranteed to put it at risk, and probably shorten its life. “At the end of the day, you have to make your peace with that,” one conservator said. “You have to think what art is for.”

Late last July at the National Gallery in London, the summer exhibition was winding down. In a matter of days, the installation team would begin preparing the space for the autumn show, devoted to the 15th-century Venetian painters Andrea Mantegna and Giovanni Bellini. The walls were about to be repainted, and custom-built cabinets moved in. In a ground-floor studio, two carpenters were carving and gilding new frames. A few feet away, on the other side of a locked door, visitors blithely unaware of all this industry were sipping coffee in the espresso bar.

In an office in the bowels of the building, the lead curator, Caroline Campbell, was fiddling with a battered, grubby foam scale model of the gallery’s Sainsbury Wing. The model’s walls were decorated with tiny colour print-outs of paintings, affixed with Blu-Tack.

Campbell’s plan was to show about 100 paintings, drawings and sculptures. The majority would have to travel from museums, galleries and private collections across the world; a third of these would never have been seen in the UK before. Then, once the show closed in late January, the pictures would travel, en masse, to the Gemäldegalerie in Berlin. It was a herculean effort, and the first time the museums had collaborated on a project of this scale.

“A lot of moving parts,” Campbell said, frowning at a doll’s-house Mantegna, before moving it a few millimetres along a tiny wall.

Facebook Twitter Pinterest Art handlers with Untitled (SEX) by Michael Craig-Martin during The George Michael Collection art sale at Christie’s, London. Photograph: Kirsty O’Connor/PA

By this point, she had already spent some six years planning the exhibition, after first pitching it to her bosses in 2012. Then came a hectic round of wooing – bringing the Berliners fully on board, approaching potential lenders in Frankfurt, Vienna, Los Angeles, Bristol, Brescia, Copenhagen, Sao Paolo and many other places besides. Where possible, Campbell made visits to request loans in person: the first of many human links in a chain that, she hoped, would eventually bring the works to London.

“They’re treasures, we have to remember that,” she said. “They’re giving us their crown jewels.”

A registrar at another institution highlighted the pressures of mounting a major loan exhibition. “There’s a tonne of quid pro quo, a lot of brinkmanship,” he said. “Loans can turn into bargaining chips: ‘Sure, we’ll lend you our Gauguin, but did you get our letter about your Titian … ?’”

Negotiations can drag on for years. Although the language (“loan”, “courtesy of”) sounds amiable enough, rivalries can be bitter, resembling the trading of star players between Premiership football clubs. A major international museum such as MoMA in New York has an enormous amount of leverage, because of its reputation, endowment and collection, but a small gallery with one star work can punch above its weight if it approaches the process cannily.

Even once loans are agreed in principle, the real haggling is still to come. How will the art travel, and when? Who pays for insurance and shipping? (Usually the borrower.) What kind of “display furniture” needs to be built? What kind of security systems are in place – attack-proof vitrines, alarms, guards? How about temperature and humidity?

Often, explained the registrar, the battles are internal, between an institution’s own curators and conservators. “You just know that, if it’s a 14th-century Florentine panel painting that’s too fragile to go anywhere, some curator at another museum is going to want it.” He laughed. “The moment you put something on display, it’s at risk. But then if you listened to me, we’d never put anything on display at all.”

Steadily, a loan list for the prospective exhibition comes together: definites, likelies, we-can-but-dreams. Export licences need to be procured. Some works are regarded as so important that loans need to be sanctioned at government level – when the Mona Lisa travelled to the US in 1963, it was brokered by none less than Jackie Kennedy. The politics and paperwork can be so complex that lists sometimes aren’t finalised until a matter of weeks before a show opens.

Facebook Twitter Pinterest JFK and Jackie Kennedy at the unveiling of the Mona Lisa at the National Gallery of Art in Washington DC in 1963. Photograph: MediaPunch Inc/Alamy Stock Photo/Alamy Stock Photo

Insurance is a particularly thorny topic. In the UK, many loans are covered by an indemnity scheme underwritten by the government – the Government Indemnity Scheme or GIS – which means that if, say, a visitor puts a foot through a Monet on loan from a France, the UK’s Department for Digital, Culture, Media and Sport (DCMS) picks up the bill. The idea is that British institutions don’t have to stump up for commercial insurance: the premium on a work by a major-league artist on three-month loan might be £80,000.

That system sounds sensible, but that hyperactive art market has played havoc with it. The average price for fine art at auction has nearly doubled since 2000, meaning that the costs of indemnifying works on loan has soared. The latest government figures reveal that DCMS has “indemnities in force” for artworks valued at some £18.7bn. Last year, the nation was potentially liable for £8.25bn for loans to Tate alone. (In 2017-18, Tate accounted for even more, £11.7bn; the museum pointed out that “our programme includes some of the major figures in modern and contemporary art”.) Fortunately for the British taxpayer, claims on the GIS aren’t often made, partly because it is rare for works to be damaged so catastrophically as to be unsalvageable: in the past 34 years, the scheme has paid out an average of just £46,000 a year.

In spite of these assurances, one conservator I interviewed still fretted about the works entrusted to her safekeeping: how would they cope with the journey, would they be cared for when they arrived, would that niggling ailment flare up, would they get everything they needed while they were away. Time and again when speaking to people about art on the move, I was put in mind of people worrying fondly about venturesome elderly relatives about to embark on a major trip abroad.

The modern era for globe-trotting art blockbusters began in the early 1960s, aided by the arrival of large jet airliners capable of carrying freight long-haul direct and fast. It is often credited to the Cairo museum’s spectacular Treasures of Tutankhamun exhibition – nicknamed the “grandaddy of all blockbusters” – which first arrived in the US in 1961 and spent much of the next 20 years on the move, making a stately progress across Japan, France, the UK, the Soviet Union and Germany, and attracting unprecedented numbers of visitors (Steve Martin’s sardonic novelty hit “King Tut” sold more than a million copies). Usually, the artefacts travelled in bespoke, fortified wooden cases divided between three planes, indemnified for the then-unprecedented amount of £9m (perhaps £135m in today’s money). When they came to London in 1972, an RAF plane was laid on to carry Tutankamun’s famous mask.

Curators at the Louvre were aghast after they heard that Jackie Kennedy had charmed the French culture minister André Malraux into agreeing to loan the Mona Lisa to the US in 1963 (many threatened to resign). Even the director of the National Gallery of Art in Washington DC was unwilling to take it, apprehensive about the risks. In the end, the US Coast Guard accompanied the liner carrying the painting as it entered New York harbour, and when the crate arrived in Washington, it was driven through town in a secure convoy with all traffic stopped. Even so, a faulty fire sprinkler went off while the work was in storage at the Metropolitan museum in New York, and it got damp. (Fortunately, then as now, the paint surface was protected by glass.)

Facebook Twitter Pinterest Handlers in New Orleans unpacking the gold mask of King Tutankhamun in 1977. Photograph: Granger/REX/Shutterstock

The Mona Lisa’s tour was regarded as such a success that it launched what one observer has called “a cavalcade of risky, armoured loans of never-before-travelled, shrine-like masterpieces”. In 1964, Michaelangelo’s marble Pietà (1499) travelled from St Peter’s in Rome to the 1964-65 World’s Fair in Flushing Meadows, New York, where it was displayed behind a thick glass wall, viewed by visitors from a moving walkway.

The fashion for blockbuster touring shows – what the New York Times architecture critic called in 1978 “the growth of the museum as circus, or spectacle, or cash register” – has increased exponentially in the ensuing decades, driven by funding cuts and museums’ frantic need to monetise their collections. Fifty years later, we are in a different league entirely. In 2018, the British Museum opened 13 international touring exhibitions, while the V&A had 11 shows travelling internationally and another seven on the road in the UK.

The cost might not simply be to the art being shunted endlessly around the world, but to us, the people who love and want to see it. If a spectacular show packed with fragile loans is so thronged with visitors that we never get near the pictures, despite paying £30 or more for a ticket, then we might wonder what the point is. Every so often, someone calls time on the era of blockbusters, but – Rembrandts at the Rijksmuseum, Da Vinci at the Louvre, Bauhaus 100 – they show no sign of disappearing. Granted fresh life by Instagram and performative encounters with live experience, they appear to be what many of us want from art.

Somewhere along a puzzle of corridors inside the V&A in South Kensington is a silent passageway lined by fireproof security doors and guarded by fingerprint-sensitive locks. These are the “transit” stores, where objects go when they have been called up from deep storage in order to be packed up and sent out.

Near the loading bay when I visited one afternoon was a jumble of empty wooden cases painted an austere shade of grey. Every museum has its own colour, to make identification easier: the Metropolitan in New York do theirs deep blue.

Behind the fireproof doors lay the treasures. A 17th-century Dutch landscape was resting on foam cushions, blue Wedgwood china piled on a steel rack. It looked as if someone fabulously wealthy was in the midst of a car boot sale. Scribbling notes – no photographs allowed – I nearly bumped into a classic Hans Wegner chair, before a hand touched my arm and guided me away. “When objects move, that’s when they’re most at risk,” Nickos Gogolos, the owner of the hand, said.

Gogolos is head registrar at the V&A, managing a team of eight whose job is to keep tabs on the collection, both on and off the premises. Given that the museum now lends out almost 3,000 objects a year to around 350 venues across the world (a sizeable number are long-term loans to British stately homes and local galleries), an increasing percentage of Gogolos’s job consists of handling loans.

“The job has got massively busier,” Gogolos said when we sat down in his office; I couldn’t help noticing that his noticeboard was covered in mindfulness quotes.

Facebook Twitter Pinterest Matisse’s Large Reclining Nude at the Royal Academy of Arts in London in 2001. Photograph: Peter J Jordan/PA

Shipping museum-grade art is a specialist business: only a handful of top-flight firms, among them the London-based Momart and Constantine, are trusted by major institutions. Even so, most museums also insist that art on loan travels at all times with a courier, ideally a conservator. This is known as “nail to nail”: one person stays with one work from the moment it is taken down in Room 38A of the V&A to the moment it goes on to the wall in a museum in Shanghai 5,700 miles away. Unless physically impossible, they need to stick with the artefact – or at least the crate it is travelling in – every step of the way.

The journey often begins in the grey pre-dawn hours, when couriers join the crate at the museum as it is loaded on to a secure van for onward transport. Small items such as books or manuscripts can be taken on as hand luggage, although this will require documentation and probably lengthy questioning at security. Also, the object will need its own first-class seat. “You don’t want to go leaving it in the overhead compartment,” the registrar explained. “That’s a whole other thing.”

Some sculptures are so huge, or so heavy, that the only way is by shipping container (although getting them in to Art Basel Miami, which happens in early December, the tail end of hurricane season, makes that risky in different ways). More often, though, artworks travel as air freight, which means arriving at the airport at least four or five hours in advance and monitoring the crate being lifted into the belly of the aircraft. If possible, it will be booked on a regular passenger flight, which means the courier can travel with it. If the crate is too large, then space on a freight plane with higher clearance must be booked.

None of this comes cheap, needless to say: getting a single object to the UK from Australia and back might cost £60,000, while trucking works from France might cost £25,000. Shippers request “must-ride” status for their artworks to avoid the risk of them hanging around in airports, but it can still be trumped by higher-priority cargo. The registrar told me: “Horses tend to win, because they have to travel same-day, and no one worries about the cost. I had a case recently where they’d lost the forms at the airport and were going to bump my shipment. I nearly lost out to some fresh fish.”

The registrar recalled one courier who watched his crate go on, signed the paperwork – and then missed the flight. “He called me from the departure lounge, saying that the work he was meant to be couriering had just taken off. I was like: ‘You had one fucking job … ’” (In 2010, a courier lost a portrait by the 19th-century French artist Corot worth some £850,000 while drunk in a New York hotel bar. It turned up a few weeks later.)

Assuming they have both made it to the destination, the courier watches the crate leave the plane, before joining it in another climate-controlled truck for transit to the host museum. If an overnight stop is required, either a secure, climate-controlled fine art warehouse must be booked en route – there is a network of these across Europe, owned by different shipping firms – or, more likely, someone stays in the truck at all times, to the extent of sleeping in it.

Even a medium-sized exhibition may contain 80 artefacts, each of which needs to reach its destination at exactly the right moment (installations for a major show are so tight that courier arrivals are booked on an hour-by-hour schedule). Multiply that by the number of touring exhibitions – the V&A currently has 12 on the road – and you can see why a registrar might be in need of a mindfulness poster or two.

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“If you’ve got a lorry with three Matisses stuck in snow in Latvia, that’s stressful,” the registrar said. “Once I had a loan that was travelling through the US and the lorry broke down in the middle of Texas; the spare part had to come from somewhere four hours away. They sat by the side of the road. I just had to pray no one knew what the cargo was.”

Amid all this, the artwork itself should barely notice it is being moved. Most cases are made of plywood and contain multiple layers of cushioning foam insulation. Although lenders will specify a stable temperature of around 20C for display, achieving that during shipping is usually impossible – so the aim is to keep the amount of time a crate is out of the gallery to a minimum. (Technicians talk of a case’s “temperature change half-time”, the time it takes for its interior to change by 50%.)

Although shippers book special “air-ride” lorries, shock absorption is also key. The Getty Institute in LA has pioneered “seismic mitigation”, employing vulcanised rubber originally developed for the Space Shuttle. Tate technicians have led the field, attaching accelerometers to fake paintings and flinging cases off high platforms to see how they cope. (“Very therapeutic,” said the former conservator who had done the research.) One case was toppled 17 times before the painting inside began to show evidence of cracking, and the research suggested that “the average painting” can survive G-forces of up to 50G, more than a 90mph car crash. “Most cases are tall and thin,” said the former conservator. “Topple is far and away your biggest risk.”

The most high-tech cases have in-built shock monitors, as well as tracking devices. When the Mona Lisa went to the US in 1963, its case was designed to float, should the liner ferrying it across the Atlantic go down.

Given the value of museum-grade art, security is taken as seriously as you would expect. In most European countries, works travel by road with armed guards either in the truck or following in a chase car. “Italy quite likes a big drama – police convoys, stuff like that,” said Nicola Moorby, a former Tate curator. “In America, there can be a fair bit of machismo: someone perching on top of the palette with a gun. Someone once said to me: ‘If anything happens, just stay in the car.’ I remember thinking: ‘You know, I’m not paid enough for this.’”

In the UK, said Gogolos, the preference was to keep things low-key. “Do you know when the crown jewels leave the Tower of London? Of course you don’t. It’s not as if the truck says: ‘There’s a Monet Inside’.”

Moorby recalled “someone going at a crate with a power drill, and I had to step in and say: ‘Uh, we don’t do that’ – screwdrivers only. There are horror stories: crates being left on runways or couriers being stranded. But honestly, with major museums, it’s so tightly planned that things very rarely go wrong. During training, they show you a video – an unremitting stretch of autobahn seen through a truck windscreen. That’s what it’s mostly like, to be honest.”

Still, there are slivers of poetry. One of her most memorable trips involved taking a major Dalí to a palazzo in Venice for a temporary exhibition. The only way for it to come in from the airport was by open barge, like a Tintoretto or Titian, centuries before. “We had this beautiful dramatic entrance up the Grand Canal by moonlight, straight into the back of the gallery. You think: ‘I can’t quite believe I’m doing this.’”

Facebook Twitter Pinterest An installation in Venice during the 2017 Biennale. Photograph: Zsolt Czegledi/EPA

Art objects have always travelled. But the logistics have always been troublesome. When Michelangelo’s David was transported from the artist’s studio to the Piazza della Signoria in May 1504, less than half a mile, it took a team of more than 40 men almost a month to get this “giant of marble” upright. The problem of shipping larger works was solved in 15th-century Venice, that most internationally minded of cities. Venetian painters had always struggled with the lagoon’s damp and salt-laden climate – terrible for both frescos and panel paintings, which either failed to dry or warped when they did. In the 1470s, artists began to experiment with an alternative medium, in plentiful supply because of its use as sailcloth: canvas. Canvas had a miraculous property: as soon as a painting was dry, it could be rolled up for dispatch to the client, who would have it re-stretched and framed.

Accidents continued to happen. In 1580, Tintoretto ran into trouble with one of his recently completed masterworks, the eight-part Gonzaga cycle, after the first four paintings arrived in Mantua damaged – seemingly because they had been rolled while still wet, then dispatched by wagon over pot-holed roads. A surprisingly large portion of Titian’s correspondence with one of his greatest patrons, Philip II of Spain, is devoted to the intricacies of shipping.

An oil painting attributed to the 16th-century court painter François Bunel and now in The Hague depicts an artist’s studio. Figurines jostle on a shelf; still lives and landscapes line the walls, waiting to be hoisted down. Ten or so sweating, struggling men, with framed paintings strapped to their backs, are trudging off into the world. It is one of very few depictions of what seem to be professional art handlers in western art.

Once a crate has reached its destination, the handlers take over. At big museums this will be an in-house team, but many shipping companies now employ their own handlers, who look after every stage of the process, for art fairs and private clients as well as galleries. The job might require lifting a half-tonne Assyrian stone relief with a mechanical hoist and manoeuvring it down a narrow corridor. Or it could involve repositioning a pocket-sized contemporary painting a few millimetres up a wall.

Some handlers I interviewed referred to their craft as an art; many, indeed, are artists, working as handlers to pay the bills. It is an irony of the art world that while the work’s dimensions and physical materials – canvas, marble, plywood, paper, neon – are painstakingly recorded and displayed, the army of people who ensure that no harm comes to them are almost always nameless. “You don’t do it for the glamour,” one handler who works for a major New York museum told me wryly. Like several others I interviewed, he had no wish to be identified: he’d lose his job.

One handler who was happy to be named was Mikei Hall, frequently spoken of with reverence within the tightly knit world of British art installation. Now a senior handling technician at Tate, he has worked at the gallery for 30 years.

We met at Tate Britain one quiet autumn afternoon. As we strolled through swarms of schoolchildren, he confessed that he sometimes found it hard to look at work in its own terms. “I’ll see something, and think: ‘How have they done that?’”

Experienced handlers will plot the choreography of people involved in carrying an object from the second it leaves the basement stores to the moment it reaches the right spot in the gallery. Checking that the work will actually fit through the doors is an important part of the job: one conservator I spoke to remembered a corporate collector who had miscalculated the size of their Rothko, and been forced to take it off its stretchers and roll it up to get it into the right room. “Double-handling” (touching things more than once, thus increasing the risk) is avoided at all costs.

“Your job is really to make everyone feel comfortable,” the New York handler said. “Nothing’s going to get damaged, the curator’s relaxed, the artist is relaxed, people are doing things gracefully and carefully and precisely.”

Like humans, works of art need time to recover after long journeys, and are usually brought into the galleries 24 hours ahead, to acclimatise before unpacking. As soon as the crate is opened, a “condition check” will happen, to make sure nothing untoward has occurred – usually comparing the work with photos or diagrams that chart pre-existing damages such as delamination of the paint surface, known as “tenting”, or “crizzling”, glass disease.

Damage in transit occurs, although naturally no one wants to talk about it. Art fairs and auction houses are notorious for slipshod handling – “it’s all just product to them,” said the conservator – and some commercial galleries aren’t much better. When we spoke, she had recently finished restoring a water-damaged painting that a security guard had left under an open skylight. Forklifts are lethal, she explained: “One wrong move and they’ll go straight through the case.”

Facebook Twitter Pinterest Henry Moore’s Oval with Points (1968-70) being installed for an exhibition in Kew Gardens in 2007. Photograph: Cate Gillon/Getty Images

The bane of her life was bubblewrap, which leaves indentations even on dry paint. Recently, a collector too cheap to pay for a proper crate while shipping a painting had fashioned his own out of cardboard lined with bubblewrap, ruining the work.

Some works, particularly modern ones, aren’t all that well made to begin with. Papier-mache from the 1970s is notoriously fragile, and pre-1980s sculptures that contain electrics are infamous for dodgy wiring. Damien Hirst’s preserved-animal sculptures are known to leak gaseous formaldehyde (although not at noxious levels). Hirst’s “fly” paintings, made by gluing thousands of insect carcasses to canvas, are rumoured to have a habit of shedding flies. “Plus, they smell awful,” another handler I interviewed said. (Hirst’s gallery, White Cube, said: “It’s not common for flies to become dislodged or fall off.”)

Still, Hirst probably holds the record for most-travelled art work: an aluminium spot painting of his was installed on the 2003 Beagle 2 probe destined for Mars, where it was used to calibrate scientific instruments. When the probe crashed on the planet’s surface the following year, the work was lost, in what might count as the priciest art-handling accident of all time.

Many historic museum buildings are not designed to house the heavy, large-scale contemporary works that are now commonplace, meaning the walls or floors have to be reinforced, or complicated crane strategies devised to squeeze works in through windows or lift them over roofs. Ai Weiwei’s 2015 Royal Academy retrospective involved Momart technicians lugging 90 tonnes of steel rebar in boxes up the ornamental staircase (these artworks, at least, weren’t fragile). Getting large sculptures into the Venice Biennale, the central section of which takes places in the medieval Arsenale complex, is notoriously difficult, requiring specialist cranes with legs that sit in the mud of the lagoon.

In June 1970, a three-and-a-half tonne Alexander Calder sculpture was being lowered into place at Princeton Art museum when the base of the crane collapsed; two engineers died. The following year, at Minneapolis’s Walker Art museum, an eight-foot square slab of steel plate, half of Richard Serra’s monumental Sculpture No 3, broke loose from its support and fell on to a rigger, Raymond Johnson, killing him. (The artist was exonerated, and the fabrication company were found negligent.)

Another handler I spoke to recalled unloading a large Anselm Kiefer painting from a truck. “It was absolutely massive, took 10 guys, and there was a really sketchy moment when the wind got up. It nearly went over; even in those massive cases, there’s a lot of flex. They always say, if it starts to move, get out of the way. Art isn’t worth anyone’s life. But those things are so expensive, you know? If it gets dropped you’ll definitely get sacked.”

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Ideally, a work will travel with extensive documentation detailing how it should be assembled, stage by stage, like an elaborate version of Ikea flatpack instructions (usually printed documents, although videos are increasingly common). But – and anyone who’s ever assembled an Ikea flatpack can empathise – handlers often have to make it up. If the artist is alive and available to consult, great. Otherwise, they and the curators have to improvise.

Given the pressures, I asked the New York handler what the satisfactions were. “You get to unravel the magic, in a way,” he replied. “You see the backs of paintings, how things are assembled. You have a Cézanne or Picasso in your hands, and you’ll see a little sketch, or how they’ve reused a bit of canvas.” He laughed softly. “It’s intimate, you know?”

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