We have never seen the structural devastation of an entire major city, like this, in our history. Galveston around the turn of the century pales by comparison, as does the explosion of the munitions ship down in Texas City way back when.
I doubt a small yield nuclear bomb would have caused the same structural devastation as New Orleans has suffered. At least people will be able to return after the recovery, which may not be the best thing. Because another huge storm is almost a statistical certainty to recur there during the lifetime of some of the younger residents.
The lesson that should be learned is that no matter how much you prepare and try to defend against it, there are some places that are inherent death traps in a storm of this magnitutde. The Big Easy is one of them. Civil engineers and disaster experts have been predicting something like this for as long as I can remember. City planners put their faith in a dubious levee system that they thought "should" hold against a Cat 3 storm.
Camille, Andrew and Ivan were wake-up calls, but no one in NO answered the phone
One of these days, a strong Cat 3 is gonna pinwheel up our way and make people rethink the wisdom of living on level ground (let alone on low lying ground) within a mile or so of the coastline
It is almost a sure thing to happen in the lifetime of many of us.