I watched it on Youtube. Somewhat interesting but very much overly melodramatic. Not nearly as interesting as the book The World Without Us (that probably inspired the show). I think they overestimate the degree to which human presence would fade. For instance, millions of tons of plastic in the oceans will continue to kill marine life for thousands of years. An intelligent alien species would easily detect the artificial nature of radioactive waste, much of which will still be lethal when the sun expands to the point where Earth is swallowed up. Plastic, especially that which is buried, will also last thousands of years at a minimum. Bronze items may still be recognizable for many millions of years. Mount Rushmore will be impressively intact for hundreds of thousands of years and still be recognizably artificial for perhaps several million more years. Glass could endure for tens-hundreds of thousand years, even millions (if it's not broken or weathered it will still be glass). This doesn't even consider the possibility of artifacts or bodies being fossilized.
Still, it's overall an entertaining program.
