Where would you start rebuilding?

[Mortblanc]

The thought that any person will determine when and where civilization will spring up or continue, or that any thing that happens will end the existence ???

Almost every one of the major cities in England predate and/or survived the fall of Rome! Colchester was already there when the Romans arrived. Constantine was crowned in York and London just celebrated its 2M birthday.

And you have several villages that date their existence back to the late stone age, early iron age and the original Celtic invasions. There's even a cave man over in Cheddar that still has DNA walking about on the green.

Civil wars, invasion, famine, plague and pestilence, the cities and communities are still there.

Cities grow up based on the needs of communication and commerce and they do so in spite of the folk that don't like crowds.