Our favorite website for everything in Philadelphia is: www.visitphilly.com. This is an excellent resource to see what is happening here from a historical visits to an underground jazz performance.
Excellent video, detailing some of the tourist attractions in our wonderful and friendly city:
Broad Street cuts Philadelphia in half (look at the map) and passes right through the City Hall. Here is a video of driving from South Street on Broad St, around the City Hall and towards the North Philadelphia: