. The first World War was the first modem industrial war. In this war, machine guns, tanks, aircrafts, chemical weapons were used on a massive scale. . Millions of soldiers were recruited from around the world and were brought to the front in ships and trains. . About 9 million civilians died and 20 millions were injured. . Most of the killed and injured were men of working age, reducing the able-bodied workforce in Europe. . During the war, industries were reconstructed to produce war related goods. . Britain borrowed large sums of money from US banks. Thus, the war transformed the US from being an international debtor to an international creditor.