Day Capsule · Hill 88 → the batteries → a cupola of 1,600 coffers

The Headland
Is Hollow

Everything on this headland was built to be invisible from the water, which means it was built into the ground — and what that leaves is architecture you photograph from inside its own tunnels. Then across the bridge to the opposite move: concrete poured thin enough to hold light up. Same material, both directions.

When
A Saturday
Light
07:00 up · 19:03 down · late Sept
Moving on
Driving from the city · ~48 mi round
Frame
Ricoh GR IV · B&W
01

The Threads

what the day is really about

The batteries are the rare case where the good light and the open hours are not in competition, because the open hours are for the INSIDE and the light is for the outside. Shoot the ridge at dawn, go underground at noon when the sun is useless, and cross the bridge for the last hour.

Buried
Buildings you photograph from inside
Battery Townsley put two sixteen-inch naval guns under forty feet of concrete and earth so they could not be seen or hit from the sea. What is left is a structure whose exterior is a hillside and whose interior is a corridor — so the frame is almost always a tunnel mouth with the ocean in it, hard contrast, the opening doing the composing.
Cold
A ridge that was pointed at the sky
Hill 88 was a radar station for the Nike missile batteries below it, abandoned and stripped. Bare platforms, stair runs, and a horizon with nothing built on it. It is the highest thing here and the emptiest — the ridge line against sky is the whole picture, and it wants first light.
Thin
The same material, poured the other way
St Mary’s is eight hyperbolic paraboloids five and a half inches thick rising a hundred and ninety feet, and a cupola made of 1,600 pre-cast triangular coffers in 128 different sizes. Nervi ran the numbers, Belluschi drew it, and it opened in 1970. After a morning of forty-foot walls it is the same substance doing the opposite job.

And under it, one rhythm: concrete as armor → concrete as ruin → concrete as light. Forty feet thick, then abandoned, then five inches and holding up a cross of glass.

Dawn on the ridge. The gated hours in the dead light. Finish inside.

Teaches · Let It Go Black — after Ray Metzker

02

The Map

where it all is · tap a point for its leg

Open the whole day in Google Maps ↗ — in order: Conzelman Rd · Field Rd · Bunker Rd · Gough St. It routes from wherever the phone is, and every spot below links its own leg the same way.

Tap any point for the leg it belongs to. Everything in Marin sits inside four square miles of one headland — the driving is short and steep, and the last hop is the bridge into the city. About forty-eight miles round, nearly half of it the run home.

06:34
blue hour begins
07:00
sunrise · Hill 88
07:35
golden ends — the ridge is done
12:30
your one door · 1st, 2nd or 3rd Saturday
15:30
the doors shut — back to open ground
18:28
golden begins · Gough St
19:03
sunset
19:29
blue ends

Pick your Saturday and you pick your door. The three gated sites here open on three different Saturdays and never on the same one: Nike SF-88 the first (12–3), Battery Townsley’s tunnels the second (12–4), Point Bonita the third (12:30–3:30). You cannot have two of them, so stop trying — choose the one you want and let it own the middle of the day. Everything else here has no door at all: the ridge, the unfinished casemate and Townsley’s exterior are open whenever you are. Saturday itself is set by St Mary’s, which runs to 18:30 on Saturdays and 17:00 the rest of the week.

03

The Day

three legs · armor, then ruin, then light

A day trip's unit is the leg, not the day — each carries a locator map, its theme, and an energy read. A gold pill on the clock means that time belongs to someone else: a door that opens or a slot that was booked. Everything unpilled is a suggested shape, not a schedule.

Leg I · Ridge — the empty top
A stripped radar station and an unfinished casemate, both facing an ocean with nothing on it.
Leg 1 · Ridge
05:30–08:30
First light
the peak

The only hour that matters, spent on the only stop that has no door.

05:3030 min
Out over the bridge
  • the bridge → Alexander Ave → Bunker Rd · ~11 mi, ~30 min
  • empty at this hour · the road is one-way westbound at the top
  • coffee before you leave — there is nothing on this headland

Through the tunnel into Fort Cronkhite and park at Rodeo Beach. The climb starts there — Miwok up onto Wolf Ridge, about two miles and 937 feet, which is why this leaves at half past five.

06:002h
Hill 88 · the ridge at blue and goldAnchor
  • park at Rodeo Beach / Fort Cronkhite · free
  • ~2 mi and 937 ft up — budget 50 min, leave in the dark
  • blue 06:34 · sunrise 07:00 · golden ends 07:35

An abandoned Cold War radar station on the highest ground here — concrete platforms, stair runs, railing stubs, and nothing standing above them. It is the emptiest thing on this list and that is the point: the ridge line against a bare sky is the frame, and it only works while the light is still coming in sideways. 🔴 It is a real climb — two miles and 937 feet from Rodeo Beach — so start up in the dark to be in position by 06:34, and do not treat this as a roadside stop.

08:0030 min
Battery Construction 129 · the one they never finishedAnchor
  • Conzelman Rd, above the bridge · free, always open
  • 5 min from the ridge gate

A WWII casemate that was never completed, so it never got its earth cover or its guns — what is there is raw poured concrete with the formwork lines still in it, open to the sky, above the bridge towers. The unfinished state is the subject; everything else here is buried and this one is not.

Leg II · Gated — the hours somebody else sets
Two doors that open at noon, and a beach in between while the light is useless.
Leg 2 · Gated
09:00–15:15
Ranger hours
steady

The dead middle of the day, spent underground on purpose.

09:001h 30m
Battery Townsley · the outside of itAnchor
  • Coastal Trail from Rodeo Beach lot · ~0.5 mi uphill
  • the exterior is free and always open
  • the TUNNELS are 2nd Saturdays only, 12–4

San Francisco’s largest WWII fortification: two sixteen-inch guns under forty feet of concrete and earth, with more than a hundred men living in the tunnels under them. Today you get the outside — the gun blocks, the blast apron, the tunnel mouths sealed behind gates. That is still the best exterior on the headland, and the mouth-with-ocean-in-it frame is available without anyone unlocking anything.

10:451h 15m
Rodeo Beach · wait out the sunCup
  • Rodeo Beach lot · free
  • food: there is none — bring it

Between the exterior and the doors opening there is an hour and a half of flat overhead light, which is the correct time to eat a sandwich on a black-sand beach and not take photographs.

12:302h 45m
Your one door · whichever Saturday this isAnchor
  • THREE SATURDAYS, ONE DOOR EACH — never two
  • 1st Sat · Nike SF-88, 12:00–15:00
  • 2nd Sat · Battery Townsley tunnels, 12:00–16:00
  • 3rd Sat · Point Bonita, 12:30–15:30 · ranger talk 12:15
  • all free · all volunteer-run — confirm the week you go

Whichever Saturday you picked, this is the block it fills. Point Bonita (3rd) runs out along a knife of rock and through a tunnel cut by hand in 1877 — 🔴 the suspension footbridge is CLOSED until further notice, so the lighthouse itself is unreachable, but the tunnel is the better picture anyway: a black arch with a bright ocean at the end of it. Nike SF-88 (1st) is the only restored Nike site in the country and the missile elevator still runs — blast doors and painted steel under flat fluorescent light. Townsley’s tunnels (2nd) put you inside the forty feet of concrete you photographed from outside in the morning. Three different pictures; one per month.

Leg III · Thin — concrete poured the other way
Back across the bridge to eight shells five inches thick, and a cupola of 1,600 coffers.
Leg 3 · Thin
15:45–19:30
The room
the peak

The stop that answers the whole morning.

15:4530 min
Back over the bridge
  • Bunker Rd → the bridge → Gough St · ~11 mi, ~30 min
  • Saturday traffic southbound — leave a buffer

Off the headland and straight down into the city. Cathedral Hill is five minutes past the bridge touchdown.

16:151h 45m
St Mary’s · inside the paraboloidsAnchor
  • 1111 Gough St · free · street parking
  • Saturday to 18:30 · other days to 17:00
  • no flash · tripods restricted · a working church

Eight hyperbolic-paraboloid shells, each about five and a half inches thick, rising 190 feet and meeting a cross of stained glass. Nervi designed the cupola’s 1,600 pre-cast triangular coffers — 128 different sizes — to carry the load, and the result is a ceiling that reads as one sweeping curve against a grid. That combination is the exact thing your Getty frames keep finding. Shoot straight up first, get it out of your system, then find the frame where the curve cuts across the grid rather than sitting inside it.

18:151h 15m
The outside, at gold and blueAnchor
  • the plaza on Gough · free
  • golden 18:28 · sunset 19:03 · blue ends 19:29

The exterior is a white saddle shape with almost nothing on it, which means it takes low light like a piece of sculpture and goes to a clean silhouette after. Stay for blue — the interior lights come up through the glass cross and it is the only moment the building reads both ways at once. You are twenty minutes from anywhere in the city; there is no reason to leave early.

04

The Spots

where to stand · what the light does · who built it

Everything here is free. The two gated sites are ranger-run and their hours are the only clock on the page — check them the week you go, because a volunteer schedule moves. Tap a spot’s map for driving directions.

Hill 8806:34 – 08:00a stripped radar station
Stand
On the concrete pads at the top, ocean behind you, the ridge running out of frame. It is a 937 ft climb — start up in the dark.
Light
Blue at 06:34, sun at 07:00, over by 07:35 — and 50 minutes of climbing before any of it. This stop does not work later.
Frame
The ridge line against bare sky. Put the platform edge low and give the sky two thirds.
See
The emptiest built thing on the headland — and the only stop today with no door and no schedule.
three frames to come back with
The stair run going up into nothing
The platform edge cutting a bare horizon
Back down the ridge with the fog sitting in the valley
Rodeo Beach / Fort Cronkhite free · ~2 mi and 937 ft up via Miwok and Wolf Ridge · budget 50 min · no facilities Directions
Battery Construction 12908:00 – 08:301943 · never finished
Stand
Inside the open casemate, shooting out toward the bridge towers.
Light
Early side light still raking the formwork. By nine it flattens.
Frame
The formwork lines in raw concrete — this is the only unclad structure here.
See
A gun emplacement that never got its guns, its earth cover, or its war.
three frames to come back with
Formwork board-marks across a whole wall
The casemate opening with the bridge tower inside it
Straight up at the unfinished roof edge
Conzelman Rd pull-out free · always open · 5 min from the ridge gate Directions
Battery Townsley09:00 – 10:301940 · under forty feet of concrete
Stand
On the blast apron in front of the gun blocks, or at a sealed tunnel mouth.
Light
East light behind the hill keeps the concrete open and shadowless until about eleven.
Frame
A tunnel mouth with the ocean in it — let the opening do the composing.
See
A building whose exterior is a hillside — and the exterior needs no ranger. The tunnels behind it open the second Saturday only, 12–4.
three frames to come back with
A sealed mouth as a black rectangle in a green hill
The gun block from below, sky above the lip
The apron running out of frame toward the sea
Rodeo Beach lot free · exterior always open · tunnels 2nd Saturday only · ~0.5 mi uphill Directions
Point Bonita12:30 – 15:30 · 3rd Sat1877 · a tunnel cut by hand
Stand
In the rock tunnel, shooting out. The platform beyond it is the second frame.
Light
Flat midday, which is exactly right for a black arch against a bright sea.
Frame
The tunnel as a hard black arch with the ocean burning at the end of it.
See
🔴 Third Saturday only, and the suspension bridge is CLOSED — the lighthouse is unreachable. The tunnel is the better picture regardless.
three frames to come back with
The arch dead-center, ocean blown out inside it
Pick marks on the tunnel wall, close
The lighthouse small and unreachable past the closed span
Point Bonita trailhead free · THIRD SATURDAY only, 12:30–15:30 · ~0.5 mi out through the tunnel Directions
Nike Missile Site SF-8812:00 – 15:00 · 1st Sat1954 · the only restored one
Stand
In the magazine, underground, on the tour. You do not get in alone.
Light
None. It is fluorescent and painted steel, and that is the register — shoot it cold.
Frame
Blast doors, the elevator rails, painted floor markings. Hard geometry under flat light.
See
First Saturday only. They still raise a missile on the elevator — the launch half of the pair whose control half is LA-96.
three frames to come back with
The elevator rails running up out of frame
A blast door edge-on, the corridor beyond it
Painted floor lines converging on the magazine door
Field Rd free · FIRST SATURDAY only, 12:00–15:00 · volunteer-run · closes in bad weather Directions
St Mary’s Cathedral16:15 – 19:30Nervi + Belluschi, 1970
Stand
Under the crossing first, then back to a corner where the curve cuts the grid.
Light
Interior all afternoon; the exterior takes gold at 18:28 and blue to 19:29.
Frame
The sweeping curve against the coffered grid — not the ceiling on its own.
See
1,600 pre-cast coffers in 128 sizes, holding up shells five and a half inches thick.
three frames to come back with
Straight up: the cross of glass inside the coffer grid
The curve of one shell cutting diagonally across the coffers
The exterior saddle at blue hour, lit from inside
Gough St free entry · street parking · Sat to 18:30, other days to 17:00 · no flash Directions
05

If the Day Turns

two speeds · pick one on the morning

Every leg below carries the same day at two speeds. Dawn is the early, light-driven version; Slow starts late, drops a stop and keeps the good one. Steady is the shape written above. None of them is the failure case — pick on the morning, from how the day actually feels.

The headland
Dawn
Be on Hill 88 for 06:34. It is the one stop with no door, no ranger and no schedule, and it is over by 07:35 — every other thing today can be done in flat light and this cannot.
Steady
Up at 05:30, ridge by 06:30, batteries through the morning, whichever door this Saturday opens from 12:30.
Slow
Skip the ridge climb and start at Battery Construction 129 off the road — raw concrete, no walk, and you keep the whole midday half.
Cathedral Hill
Dawn
Give the cathedral the last two hours rather than one. Interior until the light drops, then the exterior through gold at 18:28 and blue to 19:29, when it lights from inside.
Steady
In by 16:15, out around 19:30. Saturday is the only day it stays open to 18:30.
Slow
Interior only, an hour, and go home. The ceiling is the reason you came and it does not need the sun.
06

Before You Go

the pack, and the one thing the bridge closure changes

Camera

  • Ricoh GR IV, and check the location icon before leaving
  • A torch — the battery corridors are unlit and a phone light is not enough
  • Spare battery: the day runs from 06:15 to blue hour
  • A cloth. This headland is salt air even on a clear day

Body

  • A warm layer — the headland sits in the fog belt when the city is clear
  • Shoes for the Hill 88 climb — two miles and 937 feet, in the dark on the way up
  • Food and water for the whole day. There is nothing to buy out here
  • Cash is pointless; everything today is free
Nothing here needs bookingevery stop is free and none takes a reservation — but two of them are ranger-run, and that is a schedule rather than a booking
Decide WHICH Saturday before anything else1st = Nike SF-88, 2nd = Battery Townsley’s tunnels, 3rd = Point Bonita. They never coincide, all three are free and volunteer-run, and all three move — confirm the week you go. Any other Saturday still gives you the ridge, the casemate, Townsley’s exterior and the cathedral
The Point Bonita bridge is closed until further noticeyou cannot reach the lighthouse itself — the viewing platform and the hand-cut tunnel are what is open, and the tunnel is the better frame anyway
Townsley’s exterior is open every daythe gun blocks, blast apron and sealed tunnel mouths need no ranger at all — only the tunnels behind them are gated, and those are the second Saturday

What You Got

the frames that survived the edit

The geotag gets each frame close to where it stood — close, not exact; the last hundred yards are always a hunt. What a machine can't do is the part below: which ones survived, and whether the day was worth the drive.

The frame of the day.

Which held the light better — forty feet of concrete or five inches?

Did the tunnel mouths do the composing, or did I end up shooting the view through them?

What the fog actually did, versus the plan.

After

what the day taught

Was the ridge worth getting up in the dark for?

Did the cathedral answer the morning, or was it just a different building?

Which of the three doors is worth going back for?

Where next — and at which hour, now that I know?