That's the place, alright. The spiral is a campground called Robson Meadows. edit: Hey, mojo, you're up!
I thought for sure that was in Golden Gate Park. No such luck. It's not far away, though. That's in the Presidio, right? Was the exposition 1908, or am I remembering an earthquake date? Go ahead with another one, mojo. I have to head out for a bit.