People tend to check in during these times:
Take the elevator to any floor, walk down the hall and imagine you're about to hire Sam Spade.
Great place to have an office. It was one of a handful of buildings to survive the 1906 earthquake
Make sure and take time in the lobby to check out amazing historic photographs, info on the Bldg and appreciate the remarkable architectural detail.
If you're visiting between 9AM & 5PM, be sure to stop inside to check out one of the oldest intact buildings in the city. The amount of marble decor alone is worth a peek.