The World Without Us by Alan Weisman

The very idea presented in this book fascinated the first time I heard it. The narration in the book is speculation about what would happen to the Earth and all of its inhabitants if human beings were to suddenly all disappear. The author provides a handful of explanations for such a disappearance, but none of them are particularly plausible. The idea is just to brainstorm what may happen to all of the marks of our civilization: our cities, roads, wonders, trash, art, agricultural areas, and even what happens to the wilderness that we leave behind.
Weisman uses knowledge gained from many fields of science to complete this brainstorm. He covers archeology, oceanography, and zoology, among many others. He looks at areas of the Earth that have either been untouched by humans, or left the way they are intentionally, whether for decades, centuries, or millenia. He discusses chemical composition of the many things that we will leave behind, and how those things will fare over time. He even brings up some very intriguing points about evolution, and considers what might be the next "human" to evolve once we're gone.
The book is a fantastic overview of our society and species, and catalogues in detail the devastation that we have wrought upon the Earth. It seems that if we were to disappear tomorrow, the world would be left mainly with our chemical waste, in the form of plastics, pesticides, and even nuclear leftovers. Everything else would be absorbed back into the Earth eventually, but these chemical compositions that never existed on Earth before us would remain. It's a frightening thought, and makes this book not only a tremendous catalog of the things that we have created that were beautiful, but also brings home the point that trash goes somewhere, whether or not we ever see it again. The Earth will recover from humanity's depredations eventually, but the hope brought forward in this book is that the recovery will happen while we are still here to see it.