Temperatures topped 30C this week as farmers ploughed the fields that cover the rolling hills around Caterpillar Valley.

The long valley is on the western edge of Longueval, a quintessential rural village in northern France, a few kilometres north of the River Somme.

This is prime agricultural land. Cattle and horses graze peacefully among crops of potatoes and beets. The wider region is peppered with charming Gothic towns.

Read more: New Zealand soldier who fought at Somme honoured century after his death


Many of the buildings in Longueval are newer. Much newer. Little survived the Battle of the Somme, midway through World War I.

This is the place where, a century ago this week, New Zealand troops entered what was then the deadliest battle in their country's history.

While Gallipoli resonates more strongly with Kiwis, the casualties at the Somme were worse. Some 15,000 troops took part. More than 2000 died, another 6000 were injured. They were in action for less than a month.

"To the reek of explosives which filled the air farther back among the guns was now added the stench of corpses, which lay about everywhere on and in the earth, tilled feet down by shells," Captain Lindsay Inglis wrote of the horrific scene faced by New Zealanders on the Western Front on September 15, 1916.

"Dead on both sides, swelling and sodden, mud-stained, grey and khaki uniforms were tossed in all attitudes among the earth of the parapets and heaved out behind the crumbling ditches that passed for trenches. Pale discoloured hands and limbs, stiff feet and swollen buttocks projected grotesquely from the soil.

"Obscene, disintegrated things lay about in the worst parts. Here and there the bottom of the trench would quiver hastily as one stepped on a corpse trampled under the mud. Fat, green flies, too bloated to fly, crawled adhesively on one's face and hands. Rotting clothing and equipment and shattered, rusting weapons lay about."

These were killing fields, churned by tanks, poisoned with gas, pounded by shells.
You can't escape the past. This year alone 25 tonnes of unexploded munitions have been retrieved from farms in the area. Farmers have to work around battlefield memorials.

Tomorrow, hundreds of New Zealanders will walk where once marched thousands of Kiwi troops; descendants of the dead, a New Zealand Defence Force contingent.

Longueval will host three ceremonies, including one attended by Charles, Prince of Wales and New Zealand Defence Minister Gerry Brownlee.

"More than half of the soldiers killed during the battle have no known grave," Brownlee said.

There will be a dawn service in Longueval a New Zealand commemorative service at Caterpillar Valley Cemetery and a sunset ceremony at the New Zealand Battlefield Memorial.

Longueval is ready, determined to honour the sacrifice of the men from the other side of the world. A simple black banner with a silver fern and Aotearoa written on it has been nailed to a shed in Longueval to welcome the allied travellers.

The town's mayor, Jany Fournier, helped raise it. He said he wanted to do something special for New Zealanders.

"[The centenary] is very special for Longueval," Fournier said.

"It's very special for many young New Zealanders who came to fight for France and Longueval would like to show its gratitude."

The welcome will be as warm as the French summer. Thoughts about why it's needed are chilling.