Fort Point is a great place to stop and see not only the Fort itself but the Golden Gate Bridge from angles and perspectives you otherwise never would.  I do not recall how exactly I discovered this place but I am sure it was from research ahead of the trip.  I’m very happy to have found it.  Fort Pierce is a National Historic Site.  The Fort was completed in 1861 after 8 years of construction.  

You literally are underneath the Golden Gate Bridge.  When we visited, it was not crowded at all and we could take our time and really enjoy the Fort and the bridge.