How did trench warfare in World War 1 make it a peripheral war of attrition?

Answer 1

World War One will forever be known for it's method of fighting. Opposing armies would "dig in" approx. 30 metres from each other. The area in between them was called No Mans Land, and it was a barren landscape of scattered and waterfilled shellholes, tangled rolls of barbed wire, and the rotting and decomposing bodies of each side.

The trenches themselves were 5-6 feet deep (but in the soft muds of Passchendaele, most were shallower). The trench's bottoms were covered in duckboards, which completely disappeared in someplaces. Water had a constant prescence in the trenches. At times, it was waist deep. Rats and lice thrived here. All in all, this was not the glorious war the soldiers had been rallied about. The top of the trenches had sandbags perched on the mud. This was called the parapet.

The method of fighting used involved the soldiers of one side to rush up and "Over The Top" the parapet and rush towards their enemy with bayonets drawn. After trying to avoid the hail of machine gun bullets, grenades, bursting shells and anything else that the opposing army could throw at them, the soldiers would then engage in hand to hand fighting in the enemy trench. As you can see, fighting this way was costly.

Answer 2

Because it wasn't just one big war - there were many smaller battles involved, such as the Battle of the Somme and Verdun.