Another interesting place that we visited during the architectural walking tour was the Mechanics' Institute building on Post St. As we learned during the tour, the building houses the oldest library on the West Coast, as well as one of the oldest chess clubs in the United States. If I worked downtown, I would definitely get myself a membership there, and come there during lunch time to enjoy a moment of peace and quiet.
The Mechanics' Institute building:
SF chess club:
Spiral staircases are irresistible to the child-photographer growing inside me: