If you are in downtown you have to go to the MOCA Museum and the Board, which just opened its doors a few months ago. You need to stop at the little Tokyo district and taste the local mochi. Downtown has great street art and it really looks like New York city Street. You can find whole walls painted in colors which makes great picture. But I personally think that it looks like you are in a totally different country, because the buildings are very high. Unfortunately you also find a lot of homeless people because of polital reality. A lot of them are in drug or alchohol addicts.
Homeless people live downtown, care providers come to serve them. It is a reality but homless people come as word gets around.
Other cities also have large numbers of homeless, but they may not be as visible.