The German Army's invasion of France in 1914 outpaced its supply lines. When the advance was finally halted, both sides dug in. The Western Front became a stalemate. Frontal assaults, nighttime raids, artillery barrages, mortars, and snipers were constant threats from the enemy.
However, the horrendous and unsanitary conditions in the trenches presented an unforeseen enemy. Disease, vermin, mud, and smell of thousands of men living and dying in close quarters, tormented soldiers. Dysentery, typhus, cholera, gangrene, and "trench fever" claimed many lives.
Life in the trenches was an endless cycle of nighttime maneuvers and raids. Snipers and artillery fire during the day often separated long periods of boredom. At dawn and dusk, soldiers were ordered to 'stand to' in case of an enemy assault. Chores, inspections, writing letters, or playing cards filled the day. Soldiers slept when they could. The tedium of this routine was abandoned when the order came to go "over the top."
World War I trenches were a system of fortifications supported by machine guns and artillery. A front line trench would be connected to the rear by a series of support trenches allowing supplies and men to be moved forward without exposure to enemy fire.