Editing Technology during World War I (section)

== Trench warfare ==
{{Main|Trench warfare}}
Much of the combat involved trench warfare, in which hundreds often died for each metre gained. Many of the deadliest battles in history occurred during World War{{nbsp}}I. Such battles include Ypres, the Marne, [[Battle of Cambrai (1917)|Cambrai]], the Somme, Verdun, and Gallipoli. The Germans employed the [[Haber process]] of [[nitrogen fixation]] to provide their forces with a constant supply of gunpowder despite the British naval blockade.{{sfn|Hartcup|1988}} Artillery was responsible for the largest number of casualties and consumed vast quantities of explosives.{{sfn|Raudzens|1990|p=421}}

Trench warfare led to the development of the concrete [[Pillbox (military)|pill box]], a small, hardened blockhouse that could be used to deliver machine gun fire. Pillboxes could be placed across a battlefield with interlocking fields of fire.<ref>{{Citation 
 |author1=March, F. A. |author2=Beamish, R. J. | year=1919
 | title=History of the World War: An Authentic Narrative of the World's Greatest War
 | publisher=Leslie-Judge }}</ref>

Because attacking an entrenched enemy was so difficult, [[tunnel warfare]] became a major effort during the war.  Once enemy positions were undermined, huge amounts of explosives would be planted and detonated to prepare for an overland charge.  Sensitive listening devices that could detect the sounds of digging were crucial for defense against these underground incursions.  The British proved especially adept at these tactics, thanks to the skill of their tunnel-digging "[[sapper]]s" and the sophistication of their listening devices.

[[File:A rusty sniper shield in a WWI trench used during the Battle of Vimy Ridge at the Canadian National Vimy Memorial Park 2019.jpg|thumb|A rusty sniper shield in a WWI trench used during the Battle of Vimy Ridge at the Canadian National Vimy Memorial Park 2019]]
During the war, the immobility of [[trench warfare]] and a need for protection from [[sniper]]s created a requirement for [[Loophole (firearm)|loopholes]] both for discharging firearms and for observation.<ref name="One">[https://ww1revisited.com/2014/03/16/trench-loopholes-le-linge/ Trench Loopholes, Le Linge]</ref>  Often a steel plate was used with a "key hole", which had a rotating piece to cover the loophole when not in use.<ref name="One" />

=== Clothing ===
The British and German armies had already changed from [[red coat (British army)]] (1902) or [[Prussian blue]] (1910) for field uniforms, to less conspicuous [[khaki]] or [[field gray]]. [[Adolphe Messimy]], [[Joseph Gallieni]] and other French leaders had proposed following suit, but the French army marched to war in their traditional red trousers, and only began receiving the new "[[French Army in World War I#Uniforms|horizon blue]]" ones in 1915.

A type of raincoat for British officers, introduced long before the war, gained fame as the [[trench coat]].

The principal armies entered the war under cloth caps or leather helmets. They hastened to develop new [[steel helmet]]s, in designs that became icons of their respective countries.

=== Observation trees ===
Observing the enemy in trench warfare was difficult, prompting the invention of technology such as the [[camouflage tree]], a man made observation tower that enables forces to discreetly observe their enemy.<ref name=":02">{{Cite web |title=The Journey Of The Camouflage Tree |url=https://www.iwm.org.uk/history/the-journey-of-the-camouflage-tree |access-date=2022-04-22 |website=Imperial War Museums |language=en}}</ref>