Trench warfare was extremely common during World War I. Trenches were dug as a means of protection. New technology meant that weapons could be fired from longer distances. The trenches offered some level of protection from these weapons. In addition, men inside of the trenches could place machine guns above them and still hide below for protection as they fired. Previously, soldiers firing weaponry were exposed and could be easily seen by the enemy.
During some attacks, men left the safety of the trenches and emerged to charge across enemy lines. In many cases, poisonous gas was used by their enemies. When soldiers emerged from their trenches, they had to quietly and quickly move across the land, trying to remain out of sight. Sometimes they had to get beyond barb wire and other obstacles.