WWI Examples
This image shows how WWI was a very violent war because machine guns were used. They were mostly used in trenches to either defend or to attack the enemies. They had to wear gas mask because of the gas that was used in the war.
https://www.historycrunch.com/machine-guns-in-world-war-i.html#/
https://www.historycrunch.com/machine-guns-in-world-war-i.html#/