We can easily grow some cities to around 50,000 people while we stop expanding the sizes of current cities. Again, I'm not talking about something that will be done over the next few years, but we need to consider a world where weapons of mass destruction can be controlled by terrorist groups. A missile defense system is still a long way off, but even a missile defense system cannot protect against nanotechnology where mass destructive weapons can be hand carried.

My view is that we have to realize the longterm dangers of terrorism. We absolutely *cannot* afford a major destructive event occuring in a city of millions. To avoid it, we must keep casaulities down otherwise civilization as we know it will be drastically altered by the destruction of a major populace area. Let me reiterate, this is not a danger for tomorrow or the next year, and probably not for the next decade. But, we are moving toward nanotechnology and city populations hovering in the tens of millions all over the globe will one day be at threat by terrorists of lower financial means.

How much is that threat? I don't know exactly. But, it grows with every nanotech innovation, and it can one day be real. There aren't any defense systems to prevent weapons such as those (at least none on the drawing board such as we see with nanotechnology).

But, maybe I'm being overly dramatic...

Warm regards, Harv