On November 16, 1916, the Allied high commands met at Chantilly to prepare for the great offensives of the spring of 1917, where they saw the opportunity to upset the course of the First World War. General Nivelle, supported by the British troops of Marshal Haig, set up a diversionary strategy: to trap the enemy in the center of a surprise attack at Arras. Using these quarries, the British General Staff imagines a network of underground galleries to surprise the German troops, while the French soldiers seize the Chemin des Dames on the morning of April 16, 1917.
Voluntarily enlisted since September 1915 in the name of the British Empire, the company of New Zealand Tunnellers, mostly professional miners, were about to change the course of history : These New Zealand soldiers are responsible for digging galleries for the War of the Mines in the area of Arras, they discover ancient underground quarries dating from the Middle Ages and, in view of the potential for the Battle of Arras, the British General Staff then asks them to dig tunnels to link the quarries between them, creating this network of twenty kilometers, a real city under the city.
A diversionary strategy bringing together 24,000 British soldiers protected from the fighting on the surface until the moment of the assault on April 9, 1917.