The labyrinthine network of passageways gouged into the hard-packed European soil offered precarious refuge from the ever-present threat of fast-firing machine guns and powerful artillery characterizing the deadliest military engagement in Canada's history, claiming more than 60,000 lives over four years from a country of fewer than eight million.
War diaries collected by museums and governments offer a vivid picture of life in the trenches as characterized by long periods of monotony, punctuated by intense episodes of terror, leaving soldiers constantly on edge, as poor sanitation and shoddy living conditions ate away at morale.
Far from the clean, dry sanctuaries used in training exercises, the trenches were little more than mud ditches crawling with disease and vermin, filled with stagnant water and all too often the bodies of fallen comrades.
"One got used to many things, but I never overcame my horror of the rats," wrote Pte. Harold Saunders, who fought in France with the 2nd Battalion in June 1916.
"They abounded in some parts, great loathsome beasts gorged with flesh. … A battalion of Jerrys would have terrified me less than the rats did sometimes," he wrote, invoking a slang trench term for enemy German soldiers.
"About the same time every night the dug-out was invaded by swarms of rats," he reported. "Once we drenched the place with creosote. It almost suffocated us, but did not keep the rats away. They pattered down the steps at the usual time, paused a moment and sneezed, and then got to work on our belongings."
By war's end, a complex latticework of trenches ran 750 kilometres from Switzerland to the Belgian coast.
Canadian war efforts were mostly concentrated on this western front, where such nation-calcifying military moments as Vimy Ridge and the Battle of Ypres took place.
The persistent cold and dampness from prolonged periods standing in water-logged troughs gave way to trench foot, which risked leading to gangrene and amputation.
"My first spell in the line lasted three weeks," wrote Saunders.
"My socks were embedded in my feet with caked mud and filth and had to be removed with a knife," he continued. "Lack of rest became a torment. Undisturbed sleep seemed more desirable than heaven and much more remote."
While regular rotations and rare leave afforded brief periods of respite, the inevitable return to the front line was never far away.
"Small rations and scant sleep our daily lot. Nothing but a sea of mud all around," wrote Pte. Herbert Heckford Burrell, who served with the 100th Winnipeg Grenadiers.
"Rations for dinner 1/3rd of a tin of beans! We're in the army now."
Trench-newspapers and the daily rum ration were often the only bright spots.
More than 30 soldier-produced and surprisingly candid papers of the war — including the Listening Post, the Busy Beaver and the Dead Horse Corner Gazette — served as an outlet for soldiers to play down the hardships of trench life.
Tongue-in-cheek writing was peppered with a rich lexicon of trench slang.
Grenades became potato mashers while small-calibre German shells turned into whiz bangs, described in trench newspaper prose as "a dark, elongated insect that flies through the air at a terrific pace and carries a vicious sting."
A standard-issue helmet became a tin hat: "For washing in, cooking the mulligan, baling (sic) out the trench, drawing loose rations, such as tea or sugar; and occasionally as protection for the head during bombardments."
Humour was a coping mechanism.
"Things are not so very great and Fritz (the Germans) is always feeling around with his artillery," wrote Pte. Andrew Robert Coulter in his war diary on a sodden June 20 in 1917.
"Hope he does not happen to feel our hut."