On the Eastern and Western Fronts in World War I, trenches were often dug across battlefields to completely prevent the enemy from advancing. Two conflicting sides building trenches on either side of the battlefield creates a situation known as trench warfare. Trenches could expand for miles, making one side advancing past the other virtually impossible. In fact, there are estimates of nearly 3,000 kilometers of trenches having been dug during the war.

The primary objectives of soldiers in the trenches were to keep any advancing soldiers at bay as well as maintain the structural integrity of the trenches. The area between the trenches was called No Man's Land, and to enter it at the wrong time was almost certain death. Besides being wide open with no cover while one's opponents were obscured by their own trenches, No Man's Land was often riddled with barbed wire and landmines.

Due to infectious pests and varmints, frequent flooding, and dubious sleeping conditions, life in the trenches was grueling, to say the least. Because of this, soldiers would rotate between the front lines, support trenches, and areas for resting.

After the opening months of the German invasion of France through Belgium in the late summer of 1914, the western front settled into a bloody stalemate. Trench warfare was an integral part of the fighting on this front. Both sides dug massive complexes of trenches which ran roughly parallel with each other across a front of hundreds of miles. Generally, trench warfare was a war of attrition where each side attempted to wear down the other through frequent artillery bombardments. Sporadically, infantrymen would go "over the top" to attack the enemy across a "no man's land" strung with barbed wire and pocked by bomb craters. This region was also covered by machine guns, so these assaults were incredibly costly, and often totally futile. Occasionally, the war saw massive offensives like that against the French salient at Verdun, or the Allied offensive at the Somme River. These offensives cost literally millions of lives, and were generally inconclusive. It took American entry into the war to break the stalemate created by bloody trench warfare.