New York Resources, CAD + 3D + Maps

http://www.vterrain.org/Locations/us/ny/

Site information on Manhattan, New York City. Includes:
Regional Data
State of New York
Base Maps
Aerial Photos
3D Model
Historical NY
Transportation and Infrastructure
Subway
Bicycle
WTC site

Virtual 3d Model of Manhattan:
http://upnext.com/entry.htm

Manhattan Transformations:
Mapping Manhattan Skyscraper Districts Through Time:

http://www.skyscraper.org/timeformations/intro.html

This project uses computer models and interactive animation to depict the dynamic relationship between Manhattan's skyscrapers and other layers of urban information, such as geologic formation, settlement patterns, landfill, transportation and communication infrastructure, zoning laws and real estate cycles.

Manahatta Project | Manhattan before it was a city:
http://themannahattaproject.org/

What the World would look like during global warming flood | an interactive map:
Using data from NASA, here is a Google map tool that allows you to speculate on possible consequences of global warming and rising sea levels.