This is the Murphy Windmill in Golden Gate Park, along with a house associated with its keeper. (You can read about this windmill here at Wikipedia.) It was theoretically the largest in the world at the time of its construction in 1908 (because: Americans). It was disassembled for repair for years, and so I'm still surprised to see this restored version.
Yes, I took too many photos of it, especially its blade-side. (I'm sparing you those today.) Yes, I'm just appreciating the scale and profile of it here, and the little family picnic scene in the foreground.