Nostalgia

sometimes i see a picture and a story starts to unfold almost immediately...

there was a super high-tech culture...at some point, something happened, perhaps a disease or political upheaval that turned into civil war...millenia down the line, the mega-cities and war machines still survive being made of super-resilient, long lasting stuff and the descendants of the sparse survivors eek out a pleasant, peacefull living in the quiet time after with little if no knowledge of the horrorific event of the past