Chris was nice enough to drive us across the Golden Gate Bridge where we spent the afternoon exploring the Marin Headlands.
The entire area is part of the Golden Gate National Recreational Area.
This lighthouse, built in 1877, helps guide ships through the dangerous Golden Gate from its perch on Point Bonita, the tip of a rocky finger of land that juts into the ocean west of the bridge.
The path leading to the lighthouse passes through a 118-foot tunnel (click on the photo above to see the tunnel's white-framed entrance), and it crosses a suspension bridge that was constructed in 1954 after erosion separated the lighthouse from the mainland.
Click on the map image to see the location of Point Bonita.
The lighthouse continues to function, flashing every 3 seconds and blasting a fog horn as ships approach the narrow channel.
We also stopped at Battery Mendell, part of a series of military sites built in the area since the late 1800's to protect San Francisco's critical seaport.
The battery was constructed in 1901 and equipped with a pair of massive 12-inch guns that could fire a 1,100 projectile at a target 8 miles away.
It was chilly and very windy.
Chris took in a view of Fort Cronkhite, a beach-front World War II military post, from the top of the battery.