Which military conflict was characterized by trench warfare and high casualty rates?

World War I is known for its extensive use of trench warfare, which fundamentally shaped the nature of combat during the conflict. This style of warfare involved soldiers digging deep trenches to protect themselves from enemy fire, which led to a stagnant front line and a prolonged war characterized by the inability of either side to gain significant ground.

The high casualty rates during World War I were a direct result of the combination of trench warfare and the introduction of new, more deadly technologies such as machine guns, artillery, and poison gas. Major battles, such as the Battle of the Somme and the Battle of Verdun, saw devastating losses on both sides, often with little territorial gain.

In contrast, World War II featured more mobile warfare and different strategies, while the Korean War and Vietnam War also involved various combat tactics that did not focus exclusively on trench warfare. Therefore, World War I stands out as the conflict most famously associated with trench warfare and its horrific toll on human life.