Been thinking along the lines of Planet of the Apes -but without any man made catastrophe, meteorite impact and climate stabilization- what sort of structures or evidence of our civilization would remain in five or six million years if we all just vanish? Would an intelligent species of evolved insects -or something else- find buried artifacts in the ground like we did the dinosaurs? Would ancient structures like the pyramids or Great Wall remain for that long, and would any modern things like the Eiffel tower, Burj Khalifa, or even some present day Doomsday Vaults survive that amount of time? In our digitized age, I assume that not much would remain, other than satellites maybe or I suppose any modern species that just happens to get preserved like a dinosaur did.
I read a book by Alan Weisman titled The World Without Us, which covers this very specific topic. According to it, among the very last man-made structures left after hundreds of thousands – if not millions – of years would be the Channel Tunnel between England and France. Another notable example would be the stone faces on Mount Rushmore, as well as some old steel bridges built in an era when engineers couldn’t yet calculate structural load precisely, so they simply overbuilt everything.
What about plastic?