Some signs are no longer visible from street level. I call these the Secret Signs of San Francisco.

Because construction never stops in the City By The Bay, there are some ghost signs that still exist, but are largely hemmed in by their neighbors. Here are some examples of these secret signs, shot from either adjacent buildings or captured on Google Earth. In keeping with the theme of secrecy, I have not included their addresses because finding these artifacts is part of the fun. Happy secret sign hunting!