World War I began in August 1914, pitting Germany and its allies against Great Britain, France, and their allies. Britain sent an expeditionary force of 90,000 soldiers that assisted the retreating French armies and checked the German advance. By November, however, the army held only about 20 miles of the line and needed reinforcements. Britain rapidly trained more recruits and by the beginning of 1915 a large force was available. By then, the Western front was characterized by trenches and barbed wire. These were defensive positions made necessary due to the highly destructive weaponry of modern war, such as artillery and machine guns. Trenches were mostly built with sandbags and wooden planks. From the coast of Belgium and down across northeastern France as far as the Swiss border, there were about 475 miles of trenches. Conditions in the trenches were extremely difficult: Trenches were often deep in mud and infested with vermin. Unsanitary conditions caused what was known as trench fever, and trench foot was also common. Caused by the constant damp conditions, trench foot could result in amputation or even death.

Over the course of the war, each side launched attacks on the enemy trenches. This involved going over the trenches into what was called “no man’s land”—a desolate area between the enemies’ lines.