Generally, the structures which would last the longest are either underground or made of stone. Khufu after all has diminished only 30 feet in 4500 years, and the astonishing subterranean cities in the Cappadocia region of Turkey have been around since the dawn of history.
The Chunnel and the Moscow subway system would have a a good chance of lengthy survival, though they will eventually be flooded. In the case of the NYC subway system, that will only take a matter of days.
Monuments such as Mount Rushmore, the Statue of Liberty, and Hagia Sofia will survive, as well as ceramic objects and pennies that contain substantial amounts of copper (unlike the current ones). Even paper will last a relatively long time if not exposed to air and water.
Poisonous Legacy
Of course, less palatable monuments will also survive. Take nuclear waste. Now there's something that's going to be around for a long long time. How can we warn future generations about the locations where we've stored it? What kind of sign would last for 10,000 years, and would people understand it? In 10,000 years languages will morph into unrecognizable forms.
Then there's plastic. Approximately one billion tons have been produced and all of it is still around. It doesn't biodegrade. It weathers to bits but that only means an increase in the number of creatures that can swallow it, often to their detriment. The oceans are filling up with it. The North Pacific Gyre is an expanse almost the size of Africa, covered with floating garbage, most of which is plastic.
Then there's genetically modified food, POPs and PCBs, and other unsavoury items. Humanity, we are told, has become a force of nature.
What About the Animals?
The author covers the origins of humans, and who might replace us if we disappeared. (The primate with the second largest brain, he suggests -- baboons.)
He visits the theory that megafauna such as mammoths and mastodons were extirpated by prehistoric hunters, and mentions a plan to return elephants to North America. He provides details on more recent extinctions (the dodo, the moa, the passenger pigeon), and discusses the vast numbers of birds killed each year by flying into glass windows or frying themselves on power lines. One authority says one billion necks are broken annually in the US alone. Birds will definitely do better without us.
As for our pets, cats will survive but dogs won't. Neither will cockroaches in unheated apartments, nor all those creatures that live in or on us, such as lice and numerous kinds of bacteria.
The End
The author concludes the book by mentioning the Voluntary Human Extinction Project, and the Transhumanist movement, which involves uploading our minds into machines.
Then he heads off into space, tracking the interstellar vehicles we have sent aloft -- the Pioneers and Voyagers -- which will exit the solar system and likely keep on travelling long after we are gone. So too will electromagnetic signals from Earth, including TV shows. I Love Lucy will play to the rest of the galaxy until the signal is lost in the background noise of the universe.
Physically, this well-written and wide-ranging book ends with a 30-page bibliography and a 16-page index. But it is the 14 pages of acknowledgements that gives a better idea of its scope. The author visited Chernobyl, the Korean DMZ, East Africa, a primeval Polish forest, an isolated coral reef in the Pacific, the abandoned resort of Varosha on Cyprus, the petrochemical complex stretching from Houston to Galveston, the Ekati diamond mine in the Canadian Arctic, and other places.
