Hiroshima 1945
Hiroshima 2010
Detroit 2010
So as you can clearly see, even if a city is nuked and leveled completely to the ground and tainted with radiation it can recover with time. However if blacks move into your city it is destroyed from within and deteriorates over time to the level of the rest of Africa.
If you want to keep up with the shithole that is Detroit visit our friends at detroitiscrap.com