WWII was basically an extension of WWI. WWI was remarkable in that it was the first really mechanized war, and for the time, a really huge war unlike wars before it, which is why it was called "the Great War" before WWII happened. It was a real turning point for western society.
I think you can see a big parallel in LOTR here, with the Elves/Hobbits/etc. basically being pre-industrial peoples, while the "evil" forces were industrial societies: they felled trees, burned forests, causing widespread destruction to build their society.