Why does Baltimore out of all cities have one of the worst drug problems?

baltimore
Green Poo asked:


Why? How do the drugs get there? Why Baltimore? Why Heroin? Why not NY or LA, the big cities? Can someone please explain to me how this can come about in a city that you would least expect to have a major drug problem. Seriously, they even made a show (The Wire) about drug problems and trafficing in Baltimore. Thank you.