Fort Point lies directly under the Golden Gate Bridge in San Francisco. The Park Service opens up the fort several days a week, and it’s well worth a visit. The architecture is wonderful, and the views of the bridge, the bay, and the city are fantastic.
Of course, you need to pick a day when the fog isn’t limiting those views…
I caught this guy paddle boarding on the city-side of the fort; here he’s waiting for a wave:

Paddle boarder and pelicans.
Riding that wave!

Paddle boarder catching waves off Ft. Point.
As I was wandering the Fort, I saw him surfing directly under the bridge.