...the obvious next question being "Why would any sane person ever want to visit either?"
If you'd ever go and try to live there (something everyone ought to try at least once to get over their prejudices about the place), you'd find there is a good reason to go to or pass through both these areas. As it happened, in the year I lived in Manhattan, my wife's obstetrician was in Soho, while we have friends in Harlem (in case you don't know, Harlem is a vast rennovation zone right now, with large 4-5 story brownstones going for $500K to $1 Million). Also, our parish we joined, Corpus Christi, is on 123rd St. near Columbia, which is essentially Harlem. We used to ride to the 125th St. Subway stop to go to Church.
I found it interesting that NY is the last bastion of small-time indidividual entrepreneurial capitalism. Literally every block is covered with independent small businesses and restaurants (with apartments above of course). Even many of the few larger stores were not part of the typical American chain conglomerates in areas like groceries or electronics or clothing, but were independent NYC entitities. Its something that should make every good American Capitalist proud.