world war 1 (ww1) was a bloody war. it gave us flamethrowers, steel helmets, tanks, airplanes, aircraft carriers, chemical warfare, gas masks, guide dogs, xray machiens,this war was called the war to end all wars.U boats were german submarines. this war was the first scientific war and industrial war too.Solgiers dug fox holes to get better aim at people were they couldent get them.solgiers also dug trenches so they could hide and make a base this is called trench war fare. trench war fare was good cover fire from most weapons.