OK besides this below and DEVO coming out of the Kent State massacre, what are other facts you have about the evolution of art / music /etc that wouldn't be obvious if you didn't know but, retroactively, explain and/or illuminate a LOT ?
Reminds me of how almost all the French dadaists and surrealists were WWI veterans of the trenches seriously exploring alternatives to conventional thought and language.
Rembrandt and especially Turner's later work becomes more abstract and influences the emphasis on that element in modernist art mostly because it's harder for older men to paint as precisely