If you want to see, you have to Look.
Alan Weisman wrote a book titled the World Without Us. From the web site: In The World Without Us, Alan Weisman offers an utterly original approach to questions of humanity's impact on the planet: he asks us to envision our Earth, without us.The World Without Us reveals how, just days after humans disappear, floods in New York's subways would start eroding the city's foundations, and how, as the world’s cities crumble, asphalt jungles give way to real ones. It describes the distinct ways that organic and chemically-treated farms would revert to wild, how billions more birds would flourish, and how cockroaches in unheated cities would perish without us. Drawing on the expertise of engineers, atmospheric scientists, art conservators, zoologists, oil refiners, marine biologists, astrophysicists, religious leaders from rabbis to the Dalai Lama, and paleontologists – who describe a pre-human world inhabited by megafauna like giant sloths that stood taller than mammoths – Weisman illustrates what the planet might be like today, if not for us. The web site provides an interesting look at the world without us: http://www.worldwithoutus.com/did_you_know.html