It must have been a hell of an OE. Twenty metres underground is no place to run with Spanish bulls or drink German beer, but then, for the men of the New Zealand Tunnelling Company (NZTC), sightseeing was not a priority and November 1916 was no time to take in the beauty of Western Europe.
Today, the 446-strong NZTC are long gone, as dead as the age they lived in, yet to descend in the glass lift leading to the Wellington Quarry is to inhabit their world as it was. A fossilised footprint of something so enormous, both in scale and spirit, one would hardly believe it ever existed.
Here, under the town of Arras in northern France, Kiwis from West Coast coal towns and the goldmines of Waihi fought back fatigue and danger with elbow grease and pitch-black humour. Their work? To help hollow out the most ambitious underground network in British military history.
Working around the clock, they tunnelled through almost 90 metres of limestone a day, linking a series of medieval quarries, or "bove", which would eventually conceal 24,000 troops. The Allied High Command hoped these battalions might take the Germans by surprise at the Battle of Arras on April 9, 1917.
Out of the lift, a sunless chill lingers, not just on the spine but in the corners of the mind as one imagines the tensions leading up to one of the more extraordinary diversionary offensives of World War I.
Boosted by the arrival of men from the Maori Pioneer Battalion, the NZTC not only had to carry out its work at breakneck pace, but with as much stealth as possible.
"Chalk transmits sound very well," our guide Isabelle Pilarowski informs us. "Think of the sound of the picks almost like a sonar ... so if German or New Zealand tunnellers heard one another, each would attempt to dig beneath the enemy's mine until it became ..." her hands descend, stair-like, one under the other, "... one giant, deadly game of bluff." Forty-one of the contingent died and 151 were injured as the result of German counter-tunnelling.
"In this kind of underground war, you had all the dangers of working below the surface – collapses, things becoming unstable, suffocating conditions – except now you have thousands of kilograms of explosives as well."
What shocks even more than the cold is the sense of space. At one point, below a well used to haul stones which built the original town hundreds of years ago, the ceiling rises as high as 13 metres. It is, as one English soldier described it, an underground cathedral.
"Remember," Isabelle points out, "British troops lived here for eight days, but the New Zealand diggers for six months. Whenever I think of them down here in the dark, in French, the phrase that comes to mind is les hommes tres courageux."
Ninety-five years on, the ambience is of a work ethic, carbon-dated, a giant cave-painting splashed in the colour of human sweat.
Official accounts from the Ministry of Culture suggest the NZTC's commanding officer, Boer War veteran Major John Duigan, struggled to impose a military sense of discipline on his troops, the Maori especially. Leniency was the standing order of the day, however, when it became apparent just how well these men could throw a pick: digging out not only the link tunnels themselves, but latrines, kitchens, an officers' mess and a 700-bed hospital.
"This is one of two sites which are very important to me," Isabelle says, stopping us on the duckboards in front of a cramped 300-metre passageway lined with mining carts.
"Were it open, we could follow this exit all the way out to what is now a supermarket carpark. But just the length itself ... you can imagine the New Zealanders digging this out in the dark - 80 or 90 metres a day, no machines, nothing. It was huge."
Courage was not the only ingredient at work here. The antipodean humour on display is timeless. "Waitomo" is sarcastically chiselled over one hole used to store wooden beams. In another spot, an equally dry request: "Wanted, housekeeper". Chalk is ideal for preserving your name, and historians here have recorded more than 3000 separate instances of graffiti: ranks and serial numbers, place names, etchings of wartime sweethearts.
One of the most telling is a jagged caricature - a self-portrait perhaps. The face pinned beneath a lemon-squeezer hat is both comical and nightmarish. "To aid navigation," Isabelle explains, "the New Zealanders also named the series of interconnecting tunnels after their homes - so you have Auckland leading to Russell, Wellington leading to Nelson, Dunedin, Blenheim and so forth."
Rediscovered by cavers in the 1990s, almost 5 million (NZ$9.5m) has been spent on a visitors' centre and stabilising this 300m section of what was once a labyrinth stretching for more than 20 kilometres. While it profits from state-of-the-art audio-visual displays and original artefacts, the real weight this tour carries is encased in stone.
"You can picture the British soldiers here at Exit 10, being woken up at 5.30am on April 9, 1917, after mass the night before. The officers saying, 'Get ready' two minutes before they took those stairs to No Man's Land - the shells, the machinegun fire - and the snow as well, because it was snowing.
"It's an incredible melange for the Commonwealth: the British attack, the New Zealanders digging, the Canadians at Vimy, the Australians at Bullecourt."
Back in the lift, we ascend quietly, sun-bound. The moules-frites and stepped Flemish gables of picturesque Lille are only 20 minutes away. The endless beer menus of Belgian brasseries are not much farther. Isabelle agrees there is a kind of reverse-archaeology at work here - history that digs holes in you.
"A lot of New Zealand people don't know this story, so they are surprised to stumble across these marks of the tunnellers of Arras and all this talk of Kiwis. At the end of the tour, they are often very proud, but sometimes people are crying."
"Citron presse - in France it's a drink, but presse-citron, it's the lemon squeezer. Here in the north, in the Pas-de-Calais, we know this hat well."
- The Dominion Post