The eleventh day of the eleventh month is Armistice Day. This year – the centenary of the start of World War One, French President Francois Hollande will oversee the inauguration of a memorial to 580,000 soldiers who lost their lives on the battlefields of northern France.

The memorial at Notre-Dame de Lorette is one of several in remembrance of the fallen.

But besides the countless regimental cemeteries there are other reminders of where great battles were fought.

One such place lies beneath the town of Arras, Pas-de-Calais. There, 17th century chalk quarries were brought back into to use by New Zealand soldiers

Digging 20 metres down the troops formed connecting chambers to create a massive underground barracks.

Isabelle Pilarowski is today’s curator of the Wellington tunnels:

“The idea was to hide 24,000 men under ground so they could suddenly appear and surprise the Germans who had no idea of the existence of the tunnels – it’s a veritable 20 kilometre long maze.”

For six months, the soldiers honed the caves … hidden in a cathedral of cold wet chalk waiting for the Spring offensive against the Germans.

“You have to realise they had to go to the bathroom here, eat wash and even slept here on the spot,” said Isabelle Pilarowski

And the soldiers left traces of themselves – paintings and engravings on the cave walls showing what they got up to in order to relieve the boredom.

Reporting for euronews from Arras, Laurence Alexandrowicz evoked the moment of battle:

“April 9, 1917, it is 6.30 in the morning.The 24,000 men in these tunnels will rise up from an outlet like this. Outside, on the snow covered ground, German machine guns lie ahead . But the plan worked and the allied troops launched a surprise attack on the enemy.”