Trench warfare
Trench warfare occurred when a revolution in firepower was not matched by similar advances in mobility, resulting in a grueling form of warfare in which the defender held the advantage. On the Western Front in 1914–1918, both sides constructed elaborate trench, underground, and dugout systems opposing each other along a front, protected from assault by barbed wire, mines, camouflaged trapping pits, and other obstacles. The area between opposing trench lines (known as "no man's land") was fully exposed to artillery fire from both sides. Attacks, even if successful, often sustained severe casualties.
Trench warfare
In the New Zealand Wars (1845-1872) the indigenous Maori developed elaborate trench and bunker systems as part of fortified areas known as pā, employing them successfully as early as the 1840s to withstand British cannon, muskets, and an experimental poison-gas mortar. These systems included firing trenches, communication trenches, tunnels, and anti-artillery bunkers. British casualty rates of up to 45 percent, such as at Gate Pa in 1844 and the Battle of Ohaeawai in 1845, suggested that contemporary firepower was insufficient to dislodge defenders from a trench system.