Why is WW2 important?

This is an opinion question but I will offer mine...... The most important aspect of WWI was that it transitioned Europe from rule by monarchy to other forms of government - communism, fascism, representative democracy, nazism. What was left of the monarchies were left with minor political power. The most important outcome of WWII was that it eliminated the European powers, excepting Russia, as potential world powers. France, Britain, Germany, and Italy once had aspirations of great worldwide influence. By the end of WWII reality slowly settled in that those days were ended. We are still feeling the effects of the shattered empires left in shambles by WWII. The USA has fought wars to try and stabilize Indochina, Korea, and the middle east. Eventually you may find the USA involved in an African war, that being the most unstable left over of WWII. Additionally many proxy wars have been fought by Russia and the USA in former colonies of the Europeans. The collapse of European world influence has yet to be totally filled - and power vacuums are always filled. The USA and Russia have tried to fill the gap with limited success, as noted above. Eventually this will all sort out, most likely like it has always sorted out in human history. This will involve the gradual assumption of power by regional powers who gather smaller states into their political/economic grasp. Usually one or two or these regional powers will then make a play for world power at which time they will run into a coalition of other nations trying to keep them down.