The sidewalk is made out of screws!

This would make a great clue for a San Francisco scavenger hunt. Anyone know where this was taken?
The answer in ROT13: Ryrcunag & Pnfgyr ng Pynl naq Onggrel
This would make a great clue for a San Francisco scavenger hunt. Anyone know where this was taken?
The answer in ROT13: Ryrcunag & Pnfgyr ng Pynl naq Onggrel
Would be good for http://www.flickr.com/groups/guesswheresf/