France: The whispering walls of the Western Front

"DIE HARDS," the nickname of the Middlesex Regiment, a British unit, is written in block letters above the intricately drawn insignia of the regiment.

The 16th-century labyrinth of tunnels under the village of Bouzincourt sheltered thousands of British, Canadian and Australian soldiers during the Battle of the Somme in 1916. They would sometimes spend several days resting here.

A bas-relief created by a soldier sheltering in the caves at Bouzincourt. BEF stands for British Expeditionary Force.

An intricate portrait of a man in a Bouzincourt cave. All the 2,100 names inscribed in Bouzincourt have been photographed and logged in a database by researchers at the University of Amiens.

This soldier's boot is one of many pieces of military equipment found by researchers in the Bouzincourt tunnels. Rifles, bullets, corned-beef and marmalade tins, a toilet bucket, helmets, a Royal Field Artillery badge and a toothbrush have been found.

The village of Naours, north of Amiens, is famous for its medieval labyrinth of tunnels and caves and was visited by thousands of soldiers as tourists while on leave from the frontline. The majority of them were Australian.

A total of 3,200 names of soldiers have been found penciled onto the rock walls at Naours. Of them, 2,200 were Australians. In many cases they wrote their home addresses as well as their rank, unit and service number. Interest in the inscriptions is growing, with Australian descendants travelling to Naours to see traces of their ancestors.

William Mervyn Lecky from the town of Officer in Victoria, Australia, visited Naours in 1916. The gunner in the Australian Field Artillery was killed on September 1, 1918, less than three months before the war ended. He lies buried in a war cemetery in Peronne, France.

A chapel in the underground city of Naours, a tourist attraction visited by thousands of Australian soldiers. Many towns in northeastern France built secret subterranean tunnels to protect themselves and their livestock from invaders in the region, which has been ravaged by conflicts through the ages.

Some soldiers had time to complete bas-reliefs and carvings. It is unknown who created this striking work, possibly a portrait of a soldier, in Naours.

Researchers have identified national differences in style. German inscriptions tended to be functional and infused with propaganda and references to God and the Kaiser. This one outside a bunker on Hartmannswillerkopf, in the Vosges Mountains, is from a hymn by Martin Luther. It says: "Ein feste Burg ist unser Gott, ein gute Wehr und Waffe." (A mighty fortress is our God, A bulwark never failing.)

This bunker near St. Mihiel in the Meuse department of northern France was built by a Bavarian regiment and is inscribed with the words "In Treue Fest" ("Steadfast in loyalty"), which was the motto of the kingdom of Bavaria.

French soldiers left elaborate bas-reliefs, like these tablets dedicated to leading officers and regiments, in the limestone quarries of Confrecourt, east of Compiegne.

The soldiers in Confrecourt, sheltering from the artillery fire above them, carved an entire chapel into the stone. Ominously, the steps led to the frontline.

A bust of Marianne, the French national symbol, at Confrecourt testifies to the artistry of the French soldiers who spent time here. Unlike their British and Commonwealth counterparts, the French did not tend to leave personal names or addresses. Neither did the Germans. But on all sides, most of the graffiti had one thing in common: an absence of hatred.