It is a furniture-moving nightmare which throws the travails of transporting Great Auntie Doris's grand piano into stark perspective.
Imagine shifting a priceless stone monument 5,000 miles, explaining your way through customs, securing the necessary licences and agreements before getting it to its destination. Only then does the greatest challenge reveal itself: how do you stop it falling through the floor?
This is the predicament faced by the couriers and curators preparing for the British Museum's forthcoming exhibition, Moctezuma: Aztec Ruler, beginning on 24 September. The show, the story of one of the Aztecs' most bloodthirsty leaders, features some of the most awe-inspiring and jaw-droppingly valuable centrepieces of Aztec culture travelling abroad for the first time. The public does not normally see these priceless antiquities getting from A to B: but granted access to peer behind the scenes, it becomes clear how the transformation of bubble wrap and unplugged lighting into something polished can be as edifying as the objects themselves.
Case in point: the artifact with the weight problem is the three-tonne "Teocalli of Sacred Warfare", a 16th-century ceremonial altar where the titular Aztec kingpin once parked his sacred derriere. "The exhibition space has weak floors directly over the old library, so we had to be particularly careful," explains Jack Davy, one of the Museum's rushed-looking specialists in North American history, currently helping to install the exhibition. While an academic by training (he has an MA in Museum Studies from UCL) he also gets his hands – or gloves – dirty when the need arises: shifting, moving and shimmying priceless pieces, an inch at a time if necessary. "We had to get a heavy duty forklift truck in at 6:30 in the morning," he adds. "It was a huge, team effort. When we eventually got the piece to the central space we had to lay down girders to support the floor, with double thickness wooden boards above them. There were cranes, reinforced palates, dozens of staff working in concert. It was quite an ordeal."
Davy, like many throwing their all into gearing up the show, has been working 12-hour days over the last two weeks, and is likely to continue doing so. Led by the show's curator, Colin McEwan, he and his fellow 29 staff from the museum and Mexico's Coordinació*Nacional de Museos y Exposiciones (or the INAH, a national organisation which takes its members from the Central American nation's museums) are assembling the cases, lifting the friezes and twisting the skulls necessary to make this one of the this year's most mouth-watering historic spectacles.
Getting all of the pieces into place started around 18 months ago. It was then that McEwan finalised what he wanted to bring to Britain (along with the bits he wanted to display from the British Museum's own copious collection). Once the pieces' owners (say, Mexico's Museo Nacional de Antropología) had agreed to loan them out, his curatorial partners in Mexico began packing them up and shipping them out; though the process is somewhat more difficult than stuffing your socks down the sides of your suitcase. These guys physically carry the objects themselves, or oversee contractors who carefully load them on to lorries and in to planes; the objects never leave their line of sight through the entire process.
"We start by assessing the shape of the object and then we have boxes made to order out of especially-fumigated wood," explains Miguel Báez, project coordinator at the INAH. "We don't want there to be any unexpected reactions between the packaging and the object. Then we take it to the airport and arrange for it to end up in a plane hold; we spend hours talking to the airport officials; for example if there is something fragile inside we don't want them packing a load of stuff on top of it. It can be quite stressful."
Once the product is at the other end, it is transported by lorry – again, with the requisite degree of care – ending up at the museum's loading bay. Forklift trucks elevate the bigger pieces into the exhibition room, where a conservation team checks for damage.
Then it's up to McEwan to decide where he wants all of the exhibits placed; a twist of a knife here, a turn of a bust there ("This is the point where it comes to life, where you realise whether or not it's going to work," he says).
So surely having the skills required to safely shift three tonnes of priceless carved stone makes Davy and co in high demand when it comes to helping friends move house? Apparently not, he says.
"My friends always ask me to help them move house – but rather than doing the packing, they always want me to drive the van."
Moctezuma: Aztec Ruler runs from 24 September to 24 January in the British Museum's Reading Room