In 2009, the San Francisco Museum of Modern Art (SFMOMA) found itself with a problem every museum should have. It was about to acquire the enormous collection of modern and contemporary art assembled by the late Don Fisher and his wife Doris, founders of the Gap clothing chain. After a failed attempt to build their own museum, the Fishers decided to award their holdings–roughly 1,100 works by Andy Warhol, Ellsworth Kelly, Agnes Martin and many other marquee names–to SFMOMA on a renewable 100-year lease. All the museum had to do was find somewhere to put the stuff.
Seven years later, SFMOMA has unveiled an addition that more than doubles its gallery space, to 170,000 sq. ft. And thanks to the deep well of the Fisher collection, the museum can now launch multiple simultaneous minisurveys, gallery after gallery devoted to Chuck Close, Alexander Calder, Anselm Kiefer or Gerhard Richter. (The Fishers focused on American art, with a sideline in postwar Brits and Germans.) The collection has the shortcomings of many assembled over the past 40 years: Women and artists of color are underrepresented. So is the West Coast. New York artists certified by New York galleries went to the front of the line. All the same, a gift horse of this magnitude you don’t look in the mouth.
But with the new SFMOMA something even bigger is changing. Over the past decade or so, Los Angeles has been the presumed art-world center of gravity on the West Coast. To name just a few of its heavy elements, it has the magisterial Getty, the ever expanding L.A. County Museum of Art, the shiny new Broad and an emerging Hollywood collector base, with Leonardo DiCaprio as its presiding totem and Instagram bait. But SFMOMA is a sign that the Bay Area has at last become California’s other art force field.
Last year Stanford University opened a sizable museum to house the choice postwar American collection of Harry and Mary Margaret Anderson and their daughter Mary. In January, the Berkeley Art Museum and Pacific Film Archive moved into a new home designed by the inexhaustible firm of Diller Scofidio + Renfro. And back in San Francisco, a venture called the Minnesota Street Project refashioned two warehouses to provide dozens of artists and galleries with affordable space in a city that has less every day.
But the most telling signifier is that the global megadealer Larry Gagosian just opened his first gallery in San Francisco–right across the street from SFMOMA, no less. (Talk about exiting through the gift shop.) After all, a lot of those Internet billionaires will be needing art to fill the new campuses of Apple, Facebook and Google. Now they can visit the Brice Mardens and Cy Twomblys at the museum, then pick through similar inventory on the Gagosian sales floor. To snuggle even closer to the Silicon Valley cash flow, another multinational dealership, Pace, just opened its first West Coast outpost down the road, in Palo Alto.
Enlarging SFMOMA wasn’t easy, and not just because of the $305 million price tag or a build schedule that closed the museum for three years. The only available space was a narrow lot directly behind the old building, requiring nimble thinking from the architectural firm Sn⊘hetta. Based in Oslo and New York, Sn⊘hetta is most famous for its ingenious Oslo Opera House, with sliding-pond roof ramps that double as promenades. But that delightful building sits on a wide platform at the edge of Oslo’s harbor and has room to spread out. There was no such advantage in the alley, where Sn⊘hetta fashioned a tight corset for a 10-story extrusion.
The firm also had to come to terms with the original 1995 building, designed by Swiss architect Mario Botta in his characteristic blend of weighty forms–cylinders, cubes, massed setbacks–dressed in weighty materials like brick and stone. In a typical muscular flourish, Botta deposited a stairway in the lobby atrium that you entered at floor level through a mighty portal in black granite. Two right-angled white balcony tiers floated above it, bathed in light from an enormous skylight. It was a pipe-organ altar to art, now unfortunately demolished so the addition could join smoothly to Botta’s building. Inevitably, the white maple staircase that has replaced it, which appears to float unsupported down to the lobby floor, has none of the same heft and gravitas.
In general, but with better results elsewhere in the new building, Sn⊘hetta chose not to attempt to operate in Botta’s heavy register. Airy, asymmetrical and billowing is the language they went for, announced immediately in the swelling exterior. Clad in thin panels of fiberglass-reinforced polymer, it is configured into a pattern you could call crepe de chine, thanks to long horizontal creases. Sn⊘hetta’s American co-founder, Craig Dykers, compares it to the ripples of San Francisco Bay. But whatever it brings to mind, the elaborate surface is a peekaboo feature. Because of the narrow entry corridor, you can catch only obstructed views from street level. To take in all 10 stories at full sail, you need a rooftop vantage point down the block.
Yet on the inside, that lost Botta stairway notwithstanding, the building performs on all cylinders. The galleries are inviting, and the sizable third-floor spaces dedicated to photography are like a museum within the museum. The many windows and outdoor terraces are welcome, and the bathrooms are hilarious. (Each is a single intense color and flooded with monochromatic light. Don’t miss the red.) Altogether, SFMOMA may now be the best place in the U.S. to see postwar American art. Condolences to New York. Score one for the Bay.
This appears in the May 30, 2016 issue of TIME.