This seven minute film clip from 1906, just days before the San Francisco earthquake that destroyed the city, is still worth viewing in its entirety. The complexity of street life along market street is captivating, particularly since this is the period on the cusp of the automobile era. Note the wide streets and boulevards. The number of cars is quite interesting (and note they are the fastest mode of transport on the street). Earily, most of these buildings would be gone just days later because of the earthquake.
But, even more interesting perhaps, is the story behind the film. This story was highlighted in a 60 minutes segment from October 2010 and worth watching as well.