Here is something I stumbled upon recently. It describes the effects of a nuclear detonation in a urban environment. A example has been based on a 1 MT warhead detonating 1 mile above St.Pauls cathedral in central London. If it has already come up somewhere here then I apologize:
[youtube]http://www.youtube.com/watch?v=2Lun5UVZOG4[/youtube]
[youtube]http://www.youtube.com/watch?v=J_Ew9EAG4ss&feature=related[/youtube]
[youtube]http://www.youtube.com/watch?v=Uj9c4RbeBzc&feature=related[/youtube]
[youtube]http://www.youtube.com/watch?v=2Lun5UVZOG4[/youtube]
[youtube]http://www.youtube.com/watch?v=J_Ew9EAG4ss&feature=related[/youtube]
[youtube]http://www.youtube.com/watch?v=Uj9c4RbeBzc&feature=related[/youtube]