The ones who returned rarely spoke. Loved ones were rendered distant. The old soldiers, still young men in their 20s, were unable to describe the industrialised slaughter they had witnessed for the past four years.
Only those who were there could truly know. As Sebastian Faulks wrote in Birdsong, "I saw the great void in your soul, and you saw mine."
The story of Gallipoli has upstaged New Zealand's sorrow on the Western Front. Yet it was other names from faraway foreign fields that left men quivering at their mere mention: Ypres, Messines, Passchendaele... the Somme.
A century ago today, artillery's big guns started booming over the New Zealand Division's soldiers as they huddled in their trenches, nerves jangling. Three days later, high on false hope, rum tots, and youthful exuberance, they went over the top.
The Battle of the Somme was New Zealand's first major engagement on the Western Front.
By the end of that first day, 600 of the 6000 Kiwi troops were dead. Shot in the head, entangled and bloodied in barbed wire, decapitated by shells, left where they fell, drowning in mud.
When the three-week stalemate was finally over, it would have claimed 2111 New Zealand lives, and nearly 6000 more would be wounded.
How could you sail back to the empty quiet of 'the old country' down under, and tell your parents, your aunt, your young children what you'd seen?
Dunedin piano tuner Frank Martin signed up when war broke out.
The 19-year-old was "naturally intrigued with the possibilities" and keen to get overseas, he would write in his 1968 family memoirs.
Having been in the Territorial Medical Corps, he was posted to the Otago Medical Unit as a private.
After serving at a hospital in Egypt, he was sent to the northwest corner of France - the Western Front.
On the morning of September 15, 1916 Martin was at the front line at Flers-Courcelette, part of the Battle of the Somme.
He bore witness to history, with the first ever motorised tank attack.
"They came rumbling up to the front line and nearly frightened the seven senses out of us. And they fair put the wind up the Germans when they rumbled over their front line trenches.
"And it was no wonder that the Germans were frightened for they did not know that such things existed!" Martin wrote.
Martin worked with the New Zealand No.3 Field Ambulance Unit, dealing with the savage after-effects of machine-gun fire, shells and gas.
He later described his experience with poisonous gas warfare at the Somme.
"Vile stuff and many of our chaps in the front trenches succumbed to it... There was one occasion when the Huns sent it over our lines but the wind suddenly changed and went back over the German lines and gave them a taste of their own vileness. It was like an act of God."
But most of his memoirs is dedicated to humorous episodes, linguistic experiences with local French villagers, and his long travels homes.
He described a near miss at Ypres when a German plane shot up a petrol case he'd just been sitting on, and "a Maori standing nearby said, 'Py korry Martin, you the lucky fellow,
you never get killed in this war'."
Martin ends with describing his arrival home, as a lance corporal, and "everyone seemed different".
"Dad and Mother were both so please (sic) I had arrived home safe and sound; there were so many that were never coming home and we were glad that the war was finally over."
He settled down and had a family.
In 1939, when the Second World War broke out, he knew he couldn't well talk his son Lloyd out of signing up.
Lloyd, now aged 92 and living at Radius Residential Care in Dunedin, served with the RNZAF and US 13th Airborne Division in the Pacific in the Second World War as a radio operator and airgunner on B25s.
Growing up, he'd often ask his Dad about the war.
"He would just look at me rather quizzically and say, 'Yes, I was there'. End of sentence, no amplification, no more, and he wouldn't tell me anything more than that," Lloyd said.
Frank Martin did, however, once tell his son something about the horrors he had seen.
"He said to me once that they were handling casualties after a big battle and he said the place just looked like a slaughterhouse. When I asked him, could he give me some more details about it, he said, 'No.' But he said, 'I was shocked at man's inhumanity to man'. And he left it at that. He did not dwell on that."
Lloyd and his fellow residents have been busy growing hundreds of cornflowers and poppies over the last few months.
It's been out of season for the northern hemisphere plants, so they have been watering them by hand, and moving them around the rest home's windows, catching the low sun. They have even been playing Edith Piaf to them.
This week, the residents will install the colourful flowers on a strip of grass at the front of the rest home, as a memorial to those who fought and died at the Somme.
"For 95 per cent of New Zealanders, September the 15th will have no meaning whatsoever. But it should have," Lloyd Martin says.
"Because it was New Zealand's darkest day. It wasn't worth it... It should also be remembered what our history is built on, is built on the lives of our younger generation, and I hope that it never, ever happens again, but who would know?
"You can't describe what must've happened in the minds of many of the men who came back, some of them with their minds completely blasted for the rest of their lives, and others ... they coped. Well, my father was one who coped."
Central Otago brothers Robert William Weir and James Cochrane Weir were both at the Somme.
Farm labourer James was shot in the chest in 1916. After six months recuperating in London, he returned to the Western Front.
While marching to the front lines, he picked a bayleaf growing wild in the French countryside.
He pressed it in his journal, and later sent it home to his family in a parcel with some letters.
James would survive the war. His older brother Robert was not so lucky.
During a retreat near the town of Ypres in Belgium, during the Second Battle of the Somme on April 18, 1918 - three days before his 31st birthday - he was "killed in action". Military records hold no details on the circumstances of his death.
Now, a century after the brothers went to war, their great-great-nephew Auckland sea cadet Max Lichtenstein has made an emotional pilgrimage retracing their footsteps.
Max, 17, has returned to the Somme with a pressed bayleaf from his family's Auckland garden.
He plans to lay it at the New Zealand Battlefield Memorial near Longueval on Thursday where he will do a reading at a service marking New Zealand's involvement in the Battle of the Somme, alongside Prince Charles and Defence Minister Gerry Brownlee.
"Although I never met James Weir, I feel very proud to have this link to him and everything he and his comrades did on the Western Front."
THE BATTLE OF THE SOMME
• July 1, 1916: After a week of shelling German positions, British and French forces launch their assault. Britain alone suffers 60,000 casualties including 19,240 dead.
• September 15: New Zealand Division goes over the top.
• October 4: Kiwi infantry troops withdraw from the front line.
• New Zealand suffers 8000 casualties, including 2000 dead.
• After 141 days of battle, the Allies had advanced about 9.7km on the Somme, at a cost of an estimated 1.1million dead on both sides.
Don't worry, it's warming up now.