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.
Horses in warfare
Early in the War, cavalry skirmishes were common, and horse-mounted troops widely used for reconnaissance. On the Western Front cavalry were an effective flanking force during the "Race to the Sea" in 1914, but were less useful once trench warfare was established. There a few examples of successful shock combat, and cavalry divisions also provided important mobile firepower. Cavalry played a greater role on the Eastern Front, where trench warfare was less common. On the Eastern Front, and also against the Ottomans, the "cavalry was literally indispensable." British Empire cavalry proved adaptable, since they were trained to fight both on foot and while mounted, while other European cavalry relied primarily on shock action.