World Wars of the 20th Century The failure of the Europeans to learn from the American Civil War led them to fight the same kind of war in World War I. The armies of Europe and the United States fought for four years only to end in a stalemate. Nothing was settled despite massive loss of life. Some of the techniques used were much the same as those used in the American Civil War. Like building of fortifications and digging of trenches before charging the enemy with rifle fire and the falling back to the trenches if no gain was made. The armies of World War I were the largest put into the field up to that time. The