Yeah the League of Nations was the result of the first one and it failed. Given the sheer slaughter they needed a way to forge peace as it clearly was massively self destructive.

I am not sure how true it was but I heard a theory that Europe lost much of its intellectual prominence due to so many young men dying in the trenches in WW1 - now Europe does good intellectual work now but it is more "neat thing out of Europe" as opposed to "the hotspot". I am not well equipped to evaluate the merits but the idea is interesting at very least.

Yes, after two failed attempts to conquer Europe by military force, Germans finally realized they can achieve the same effect much easier with their economical power and then created EU :)