Fall of New York. How will it be

Imagine that all of humanity suddenly somehow dies or disappears from the face of the Earth. As soon disappear all signs of human existence, as will be the process of disintegration of the material culture of man? That's what the book says Alan Weisman, "The World Without Us» ("World Without Us" by Alan Weisman), teaches at the University of Arizona. What is destroyed immediately, that in a year, and that will continue in a million years?