A long-forgotten subterranean memorial to Canadian soldiers who fought in the First World War will soon see the light of day, thanks to the efforts of a London, Ont.-based group.

The unusual memorial was made by the soldiers themselves as they slept, ate and waited in a cave in northern France. They were eventually called to fight at nearby Vimy Ridge, in what would become one of the greatest victories in Canadian military history.

The cave, which is accessible through a small hole in a farmer's field, has been sealed off and largely forgotten since the 1917 battle. British experts reopened the cave five years ago, working to preserve carvings made by soldiers along the cave walls.

Now a Canadian group called the Canadigm Team has joined them to document and to make exact replicas of hundreds of pieces of graffiti, which they plan to show across the country.

"It's important to remember the battle. But also, these are Canadians," said Zenon Andrusyszyn, a visual artist who's directing the group.

Andrusyszyn and his colleagues say the etchings by long-dead soldiers must be remembered, as they're slowly deteriorating. So they've been working to document subterranean pre-battle, First World War-era hideouts in France and are researching dozens of soldiers' stories in preparation for the centenary of Canada's victory at Vimy Ridge.

Canadigm's inaugural exhibit, titled The Souterrain Impressions, will open in the fall of 2013 and will tour across Canada for the next four years, leading up to the 100th anniversary of the battle.

CTV News was recently given access to the cave, revealing carvings that until recently were unknown to all but a select group, which included the former head of the Canadian Armed Forces.

"This is unique," said retired General Rick Hillier, the honourary chair of the Vimy Foundation. "It's part of our legacy, part of our history."

The cave itself was carved into an ancient chalk quarry. It's a labyrinth of corridors and open spaces that was once lined with hundreds of bunk beds. While the young soldiers lay there, they carved.

Alec Ambler, a young stone mason, signed his work and went on to survive the war. Many others weren't so lucky.

A soldier names Elroy Lacey drew animals he remembered from his farm in Dunwich, Ont. He was later killed in the fighting. Another carver, Grant Phelps, was a railway worker from St. Thomas, Ont. He was hit by shrapnel in the opening moments of the Vimy Ridge battle and succumbed to his wounds hours later.

Eventually the fighting ended and the cave was abandoned. But there is also some graffiti in the cave dating to 1940, as Belgian refugees hid from the fighting in the next world war.

With a report from CTV's London Bureau Chief Tom Kennedy