Trench Warfare is a technique
where belligerents create earthworks (often trenches) that protect troops from
small-arms fire and some protection against artillery. World War I is known for
that, and so European east theater became riddled with networks of trenches. A trench
well protected by other subsequent trenches and artillery makes offensives
costly and deadly to the side of attacker, and so often the conflict becomes some sort of a stalemate.
