Trench Warfare was an extremely deadly form of war were hundreds of men would get out of the mud filled trenches and run across no mans land being shot at (by snipers trench brooms Thomson machine guns) and jumping over barbwire fences only to retreat because of extreme losses. But that's not even the worst part afterwords you have to clean up the mess your living courtiers oftentimes would smell of rotting carcase and would be infested with rats. Which carry diseases and sometimes case the death of many soldier's. Some would even wear gas masks because it got so bad. Many of the weapons used in this type of warfare were vary deadly at close range. If this doesn't answer your question then i don't know what will.