Germans were the first to use flamethrowers in WWI. Their flamethrowers could fire jets of flame as far as 130 feet (40 m).
Russia mobilized 12 million troops during WWI, making it the largest army in the war. More than ¾ were killed, wounded, or went missing in action.
During WWI, dogs were used as messengers and carried orders to the front lines in capsules attached to their bodies. Dogs were also used to lay down telegraph wires.