Photographers on the Front Lines of the Great War'In 1914, as the outbreak of World War I brought mass slaughter to Europe’s battlefields, photojournalism evolved rapidly in the muddy trenches, where 19th century tactics met 20th century weapons. Machine guns, airplanes, tanks, flamethrowers, poisonous gas and submarines were widely used for the first time against doomed troops that were sent by their generals into frontal attacks that left millions dead...'