All the good topics have been mentioned...
*screws up his face*
That's not actually true. Just the bigger topics have been covered.
Here's a left field one for you.
Occupied France (contrasting Vichy France) and the impact of this on postwar French colonialism. Use Vietnam as a case study.
Or how Britain basically sacrificed its colonial possessions and position as super-power to kick Hitler out of Europe. In 1939, Britain was the
single(as in, when taken as a whole against another individual power) most powerful state on the planet. In 1945, the Empire had been bled dry and secured the positions of the Soviet Union and United States as the inheritors of world power. Turns out, conducting an almost solo effort against a mad-man who had 90% of meaningful Europe prostrate at his feet is one expensive son of a *****.
Or how Japanese action in Asia basically rung the death-knell of direct European imperialism.
Or if you
really just want to find out why I'm such a misanthropic, hateful & pessimistic *******, look up the "first reactions" of most of Eastern Europe when the Wehrmacht and SS rolled in. For those without the time, let's just say that the SS had to tell some people to
tone it the **** down. I'm looking at you in particular, Ukraine and Baltic states. In Lithuania alone, a mob formed, unprompted by Germans, where they rounded up everyone who was or they
thought was a Jew and butchered them. Then on the pile of fresh corpses, a man took an accordion and started the Lithuanian national anthem.
Spac-****ing-tacular. Just about everyone involved seemed to lose their **** and decided that it was a great time to open season on X group in one society or another.
Really, there's only one meaningful lesson to learn from WW2, and that is
nationalism is bull****. Anyone who says otherwise is either infuriatingly naive, stupid, or immediately suspicious.