Trench warfare
Trench warfare has become archetypically associated with the First World War of 1914–1918, when the Race to the Sea rapidly expanded trench use on the Western Front starting in September 1914. By the end of October 1914 the whole front in Belgium and France had solidified into lines of trenches, which lasted until the last weeks of the war. Mass infantry assaults were futile in the face of artillery fire as well as rapid rifle and machine-gun fire. Both sides concentrated on breaking up enemy attacks and on protecting their own troops by digging deep into the ground. Trench warfare also took place on other fronts, including in Italy and at Gallipoli.
Christmas truce
Truces between British and German units can be dated to early November 1914, around the time opposing armies had begun static trench warfare. At this time, both sides' rations were brought up to the front line after dusk, and soldiers on both sides noted a period of peace while they collected their food. By 1 December, a British soldier could record a friendly visit from a German sergeant one morning "to see how we were getting on". Relations between French and German units were generally more tense, but the same phenomenon began to emerge. In early December, a German surgeon recorded a regular half-hourly truce each evening to recover dead soldiers for burial, during which French and German soldiers exchanged newspapers. This behaviour was often challenged by junior and senior officers; the young Charles de Gaulle wrote on 7 December of the "lamentable" desire of French infantrymen to leave the enemy in peace, while the commander of 10th Army, Victor d'Urbal, wrote of the "unfortunate consequences" when men "become familiar with their neighbours opposite". Other truces could be enforced on both sides by weather conditions, especially when trench lines flooded in low-lying areas, though these often lasted after the weather had cleared. On the Eastern Front, Fritz Kreisler reported incidents of spontaneous truces and fraternisation between the Austro-Hungarians and Russians in the first few weeks of the war.