And the failure thereof...

Waaaay back in the early 80's, there was a very short-lived magazine called Next, which billed itself "for futurists". Apparently, they weren't able to see their own future very well...

They published an illustrated article about the longevity of human artefacts after humans had gone extinct. One type mentioned therein, which I didn't see in the current piece, was dams -- especially the big ones, like Hoover. I wonder, if one of those failed catastrophically (through decades of no maintenance), how detectable the downstream damage might be (see the Washington scablands for an extreme case in nature) after a few thousand years.

While I'm here, I'll weigh in on Tony's side about ice age erasure: Unless the Earth suffers a runaway "snowball" cooling, the glacial sheet would probably not cover all of mankind's works. As I recall, the last glaciation in eastern N. America did not reach as far south as the Ohio River. Interesting prospect, to have Southern culture remain detectable while the Yankees (not to mention the Mets, Cubs, and Mariners) are scraped from the surface.

Aside from that, think of the Neolithic cave paintings in Europe... and the graffitti in subway tubes world-wide.