The Ypres salient was a bulge in the Allied front line
As the 90th anniversary of the Armistice which brought World War I to an end approaches, signs of the bloody conflict on the Western Front are still very much apparent today.
The forests around Verdun, where so many died, are still and silent.
Nature has smoothed countryside torn up by shellfire, and undermined by the men who sheltered from it.
Ahead on the carpet of brightly coloured autumn leaves, Christina Holstein forced her way through low hanging branches to follow a trail she knows well.
Ms Holstein, a British expat now living in Luxembourg, has made the wartime history of this area her speciality and runs tours of the Verdun battlefield.
On the first day of our trip across the area, she had offered to show us how events of nine decades ago had left an indelible mark on the landscape.
Stumbling over tree roots, ducking beneath brambles, we found what we were looking for.
There in front were the unmistakeable features of French trenches - deep channels, virtually unchanged, that sheltered men struggling to and from the front line.
Here and there, the dark mouths of the dugouts that provided some safety from the shelling, or the concrete fire steps from which riflemen and machine-gunners could engage an enemy hunkered down in identical trenches less than a 100 metres away.
A quarter of a million French and German soldiers died in the savage fighting around the town of Verdun, the bones of those who could not be identified lie beneath the floor of the giant Ossuary which dominates the forest skyline .
After the war, much of the land could neither be farmed nor built on, and it was left untouched as a national memorial.
"It's the silence that I find most moving," Ms Holstein said, gazing across what was once No Man's Land.
"So much of suffering here was for so little gain, it should never happen again."
The following day, I stood high above another battlefield, far to the north-west.
Vimy Ridge stands witness to the losses sustained by men who had come to fight a war thousands of miles from home.
Ms Holstein runs tours of the former battlefields
In 1917, the Canadian Corps attacked and captured German positions on the hills around Arras. More than 3,000 Canadians died.
The shell holes and trenches are now covered by a manicured carpet of grass - Canada has adopted this corner of France as its own memorial.
The warning signs remind visitors that unexploded shells and grenades lie where they fell.
On the crest of the hill, the giant figure of a grieving mother, cut from gleaming white stone, looks down on a tomb.
A few yards away sections of the Allied and German trenches have been preserved.
Steps lead to the network of tunnels bored by British engineers, stretching back more than a mile from the front.
I stood in the semi-darkness and tried to imagine the fear and the courage of young men waiting for the whistles that would summon so many of them to certain death in the bloody chaos above.
Then onward to our final destination.
Thousands of Commonwealth soldiers are buried near Passendale
The Ypres salient was a bulge in the Allied front line.
For much of the Great War, the Germans dominated high ground on three sides, pulverising Ypres and turning poorly drained farmland into a quagmire.
Two great battles took place here, resulting in carnage on a horrific scale.
Near the village of Passendale, the headstones that mark the passing of almost 12,000 Allied soldiers line the gentle slope in neat ranks.
Standing among them, I looked down the slope towards Ypres, behind me the Cross of Remembrance has been erected on top of one of the German pillboxes that directed fire onto the Allied advance.
Beyond it, the wall which bears the names of 30,000 more men whose remains were never identified.
That evening, as is the case every night, hundreds stood in silence for the Last Post ceremony under Ypres' Menin Gate.
At its close I chatted to some of the schoolchildren who had laid wreaths.
Until now, the Great War was just another episode in their history curriculum.
Now they say this visit to the battlefields has reinforced their view that they too must not forget.