Trench warfare is a type of fighting where both sides build deep trenches as a defense against the enemy. These trenches can stretch for many miles. Soldiers generally rotated through three stages of the front. They would spend some time in the front line trenches, some time in the support trenches, and some time resting. The British said it took 450 men 6 hours to build about 250 meters of a trench system. The trenches were not nice, clean places. There were pests living in them such as rats.