What are the pros and cons of WW1 (World War 1)

On the con side of things, WWI resulted in a serious drop in young men available for work. also, germany suffered due to having to pay for expenses of war and losing any land it had gained. all other participating countries were sent into a recession due to the cost f the war, and eventually the great depression. on the pro side, the league of nations was formed and would later be called the united nations. also, WWI strengthened ties between britain and america