SEA RANCH, Calif. — It was an era of now unimaginable optimism, when one believed that architecture and planning could save the world — or at least save the environment. In 1964, a group of architecture faculty at the University of California, Berkeley, some only in their 20s, were entrusted by developer Al Boeke with ten miles of magnificent California coastline three hours north of San Francisco.

For an exhilarating historical moment the energies of postwar suburban development, an emerging ecology movement and Modernist architecture found a common purpose: transforming a 5,200 acre sheep ranch here into a progressive residential community, built in a way that was not only in tune with nature, but driven by nature.

The Sea Ranch came to be “the California architectural monument of the 1960s,” in the words of the design historian David S. Gebhard . Its first important building, the 1964 Condominium One, with its signature slanted roofs and open interiors, would make it onto the National Register of Historic Places. The Sea Ranch’s early unpainted wooden houses were minuscule in size, their charming and inventive architecture deliberately veiled by trees. Yet by 1965, a “Sea Ranch style” had taken the international design world by storm.

And in the following decade, its particular combination of the shed roof, the window seats and ladders, the ingenious overhead spaces for outlooks and skylights as well as sleeping, would be thoroughly absorbed by the mainstream.