I hope some future civilization doesn't learn about us through imprints left in the sidewalks... there are a couple rather inappropriate scrawlings in a recently-replaced sidewalk that I walk by every day which could give future civilizations a very skewed view of our society! LOL!
@digitalrn read the classic dystopian novel "A Canticle for Leibowitz" in which, hundreds of years after atomic destruction, the few people remaining struggle to understand a grocery list that survived.