Answer:

This is the base of the Murphy Windmill in Golden Gate Park.
The Murphy Windmill sits on the southwest corner of the park.
The Queen Wilhelmina Windmill (FogBay #26) sits on the park's northwest corner.


The sails of the Murphy Windmill are the longest in the world at 114 feet each.
The tower is 92 feet tall and houses 40 tons of machinery.