American soldiers in trenches, France, 1918. Trench warfare is a form of land warfare using occupied fighting lines consisting largely of trenches, in which troops are significantly protected from the enemy's small arms fire and are substantially sheltered from artillery. The most prominent case of trench warfare is the Western Front in World War I. Both sides constructed elaborate trench and dugout systems opposing each other along a front, protected from assault by barbed wire. The area between opposing trench lines (no man's land) was fully exposed to artillery fire from both sides. Attacks, even if successful, often sustained severe casualties. The common infantry soldier had only a few weapons to use in the trenches: the rifle, bayonet, and hand grenade.