Perhaps, you've seen the special on the Discovery Channel of what would happen if humans disappeared overnight. The educational documentary goes through all of our civilization, including our energy plants, our bridges, our roads, and our buildings, our dams, and theorizes on what would remain, and how fast the corrosion, rust, and decay would set in. It also asks the question of what the species that were left behind would do with our cities, as the new inhabitants and how they might adapt to their new habitats.

If you like considering things like this and you enjoyed the Discovery Channel show on this topic, then perhaps I can recommend a very good book to you. The book is about this very subject and the name of the book is;

"The World Without Us," by Alan Wiseman; Thomas Dunne Books A.D. vision of St. Martin's press.

There are some theories that human civilizations have come and gone, and a few humans have remained and then re-populated the earth. We know that there were many great civilizations of the past because we keep digging up their cities, which have been buried under rock and sediment. Perhaps, the theories are true that human civilizations have experienced global cataclysmic events, which wiped out nearly everyone.

Of course, this time humans have built incredible cities, and come up with incredible technologies, surely some of the things we built this time will remain for tens of thousands of years, or so you might think. How long would you think your city would last, if all the people left and never returned?

Obviously, the windows would eventually get broken, animals would go inside the building to live, the elements would start to cause decay from the inside of the buildings as well as the outside, and yes, eventually those buildings would fall down. Anyway, I think you will very much enjoy this book, I did, and I highly recommend it to you. Please consider all this.