Cool site!

I selected London, England and it immediately centered the blast on the Houses of Parliament. How sentient is that!

Nice to see more options on that one. This is the one I remember: http://meyerweb.com/eric/tools/gmap/hydesim.html

Not to downplay the seriousness, but that site is quite surprising. I grew up about an hour outside of DC and according to that site, greatly overestimated the danger of a nuclear blast in the nation's capital.