Given the large influence that San Francisco has on modern global culture, I expected more from the city than what I actually found.

Grace Cathedral, found atop Nob Hill, was originally designed by G.F. Bodley (who also designed Washington Cathedral). It was completed (insofar as it is complete) in 1964. A mural commemorating the founding of the United Nations in San Francisco can be found inside.
The Palace Of Fine Arts is one of the last remnants of the Panama-Pacific Exhibition of 1915 which celebrated the completion of the Panama Canal.
The Mission Of St. Francis Of Assisi was founded in 1776 (when California was part of New Spain) and gives its name to the whole city.