Since I am discussing neogeography and nukes I might was well link to HYDESim: High Yield Detonation Effects Simulator.
Using Google Maps API it is possible to test what a nuclear bomb blast would do to a certain area. Cities can be selected or you can move the target. Kilotonnage can also be customized. A information key describes what the various distance decay affects are of the explosion. Keep in mind that radiation is not considered in the program.
Scary stuff for a scary world. A missile shield does not seem to be a bad idea right about now. Most of