~Collapse of European Empires like Russia, Germany, Turkey, Austria-Hungary etc.
And the above catalyzed the formation and the independence of new nation states like Poland, Estonia, Lithuania, Lativa, Czechoslovakia, Yugoslavia, etc.
~Heavy Casualties----- over 8 million of soldiers died
~Destruction-----houses, factories, mines, farms, railways...
-led to serious unemployment, a lot of people became homeless
-collapse of economy of the country
~Development of new weapons, e.g. airships, TANKS
~The rising status of women---women could enjoy the right of voting they could now earn their own salaries and managed the household finances
And MOST IMPORTANTLY, the Treaty of versailles had generated BITTER RESENTMENT of Germany and Italy(for more reference, please refer to
http://www.johndclare.net/) and sowed the seed for the Second World War.
Hope these main point help.