Sometimes it is difficult to see what good comes of something and what lessons we have learnt for it. Perhaps it is not the lesson we want to see - an end to wars, but instead the lesson that we can stand up to evil and not let it win.
I have this portrait on my wall -
It is taken in 1940 after most of Europe had fallen to Germany and a good year before the USA came into the war. It is often forgotten that we stood alone against Germany for this time. I don't see it as glorifying or celebrating war to have this but as a demonstration of how resilient we can be.
Bad times often bring out the best in people.