If you drive across the Bay Bridge and take that sharp, somewhat precarious exit toward the middle of the span, you land on a flat piece of man-made dirt called Treasure Island. Most people head there for the flea markets or the skyline views. They usually drive right past the massive, curved white building sitting near the entrance. That’s the Treasure Island Administration Building. It looks like it belongs in a Batman movie from the nineties or maybe a high-end sci-fi flick from the thirties. Honestly, it’s one of the most underrated architectural flexes in all of California.
It’s huge. It’s semicircular. And it feels permanent in a way the rest of the island—which was basically built out of mud dredged from the bay—doesn't.
Originally known as Building 1, this structure wasn't just built to hold offices. It was designed to be the terminal for the Pan American World Airways "China Clipper" flying boats. Imagine that for a second. You wouldn't pull up to a tarmac; you’d pull up to a dock, walk through a glamorous Art Deco lobby, and board a massive plane that took off from the water. It was the peak of luxury travel before the world went to war.
The Golden Gate International Exposition Legacy
The Treasure Island Administration Building didn't just appear out of nowhere. It was the centerpiece of the 1939-1940 Golden Gate International Exposition (GGIE). While the rest of the country was still shaking off the Great Depression, San Francisco decided to build an entire island to celebrate the completion of its two massive bridges. They called it the "Pageant of the Pacific."
Architects George Kelham and William Peyton Day were the minds behind this beast. They went with a style often called "Pacific Basin," which basically mashed together Art Deco, Mayan, and even some Cambodian influences. It’s weird. It’s eclectic. It works.
While most of the fair's buildings were "temporary"—made of wood and plaster designed to be torn down after the party ended—Building 1 was built to last. It was constructed with reinforced concrete because the city originally intended for Treasure Island to become San Francisco’s permanent municipal airport once the fair was over. History, as it often does, had other plans. Pearl Harbor happened, and the U.S. Navy decided they needed a base in the middle of the bay more than the city needed a fancy airport.
The Navy took over in 1941. They stayed for over half a century.
Hidden Details in the Architecture
If you stand in front of the building today, you’ll notice these massive, stylized eagle sculptures. They aren't just there to look patriotic. They are part of the original Art Deco "Streamline Moderne" aesthetic that defined the era. The building’s curve is meant to follow the shoreline, creating this sweeping, aerodynamic feel that was all the rage when people thought flying boats were the future of transport.
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Inside, the lobby is a time capsule. You’ve got these incredible murals and a scale model of the island as it looked during the fair. There’s a specific kind of quiet in there that feels like 1939. It's cool, slightly damp, and smells vaguely of old paper and bay air.
One thing most people miss is the height of the ceilings in the main hall. They weren't just showing off; they needed space to process international travelers. This was the literal gateway to the Pacific.
From Naval Command to Movie Set
When the Navy moved in, the Treasure Island Administration Building became the nerve center for the Naval Station Treasure Island. It wasn't about cocktails and flying boats anymore. It was about logistics, training, and the Cold War. For decades, it was a restricted area. Unless you had a uniform or a damn good reason to be there, you weren't getting a close look at those Art Deco curves.
Because it looks so unique, Hollywood eventually came calling.
You might recognize the interior from Indiana Jones and the Last Crusade. It stood in for the Berlin Airport. There’s a certain irony in a building designed for Pacific travel being used to represent Nazi Germany in a movie, but that’s the magic of good architecture—it can be anything. It also showed up in The Parent Trap and various TV shows. The building has a "stature" that’s hard to replicate on a soundstage. It feels heavy. It feels real.
The Struggle for Preservation
The Navy officially pulled out in 1997. Since then, the island has been in a weird state of limbo. There’s massive redevelopment happening now—high-rises, condos, the whole "New San Francisco" vibe. But Building 1 stands there as a protected landmark.
It’s currently the home of the Treasure Island Museum. If you want to understand why this building matters, you have to go inside and talk to the folks who run the museum. They aren't corporate historians; they’re enthusiasts who care about the weird, layered history of this place. They’ll tell you about the radioactive soil issues (which are a real thing on the island, though the building area is generally considered the "safe" zone for visitors) and the struggle to keep a concrete giant from crumbling in the salty air.
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Maintaining a building like this is a nightmare. Concrete cancer—where the rebar inside the walls starts to rust and expand—is a constant threat in a marine environment.
Why You Should Visit Now
Honestly, you should go before the island changes too much. Right now, there’s a gritty, transitional feel to Treasure Island. You have the gleaming new ferry terminal just a few hundred yards away, contrasted with the weathered, slightly imposing facade of the administration building.
- The View: Walk around the back of the building. You get a panoramic view of the San Francisco skyline that is, frankly, better than the one from the Embarcadero because you can see the whole city at once.
- The Museum: It’s small but packed. You can see original uniforms, tickets from the 1939 fair, and photos of the China Clipper docking right where the parking lot is now.
- The Vibe: It’s one of the few places in San Francisco where you can feel the 1930s without a gift shop being shoved in your face.
The Reality of the "New" Treasure Island
There is a lot of talk about the "Treasure Island Administration Building" becoming a boutique hotel or a high-end event space. The developers behind the island's $6 billion master plan know that this building is the "anchor" of the island’s identity. You can't just build glass towers and expect people to feel a connection to the land. You need the history.
But here is the catch: fixing up a landmarked 1930s terminal to modern seismic standards is insanely expensive.
The building sits on a "non-engineered" landfill. In a major earthquake, the ground it's on could technically liquefy. Engineers have been working for years on "ground improvement" projects around the island to prevent this. They basically vibrate the soil and inject grout to make it solid. It’s a massive undertaking that explains why the redevelopment is taking decades rather than years.
A Masterclass in Art Deco Design
For the design nerds, look at the windows. The fenestration—how the windows are arranged—is perfectly symmetrical. This was a hallmark of the "Strips" style of Art Deco. It emphasizes verticality and power. Even though the building is only a few stories tall, it feels much taller because of those recessed vertical lines.
The building also served as a literal compass for the fair. The "Tower of the Sun," which was the fair's 400-foot centerpiece, stood directly across from the administration building. While the tower is gone (torn down in 1941), the admin building remains as the last living witness to that vision of a "Pacific Unity."
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Actionable Insights for Your Visit
If you're planning to check out the Treasure Island Administration Building, don't just wing it. The island is a construction zone right now, and navigation can be a pain.
1. Take the Ferry: Skip the Bay Bridge traffic. There is a ferry from the San Francisco Ferry Building that drops you off right near the Admin building. It’s a 10-minute ride and offers the best approach to see the building’s scale from the water—just like the old flying boats would have seen it.
2. Check Museum Hours: The Treasure Island Museum isn't open 24/7. It’s usually open weekdays and some weekends, but check their official site before you trek out there. It's located right inside the main lobby of Building 1.
3. Combine with a Walk: After looking at the building, walk along the western shoreline (Clipper Cove). This is where the sea planes used to land. You can still see some of the old ramps if you know where to look.
4. Photographers: Go at Sunset: The building faces west-ish toward the city. When the sun hits the white concrete at a low angle, the shadows in the Art Deco recesses become deep and dramatic. It’s a dream for architectural photography.
The Treasure Island Administration Building isn't just an old office. It’s a survivor. It survived the end of the Golden Age of Flight, the entirety of World War II, the Cold War, and the Loma Prieta earthquake. It’s a testament to a time when San Francisco thought it could build a brand new world out of nothing but bay mud and grand ideas. It’s worth more than a drive-by.