What was the worst hellhole of a city (or district of one) that you've ever been through? How was it so hellish?

I need to know what towns, cities, or parts of cities to avoid (but maybe observe from Google Street View.)

So when you drove through that worst part of town, how was it the worst?

Also, what unique event happened as you went through there? (Did you hear gunshots and try to floor it out of there, etc.?)