By the early 20th century, the City of San Francisco and the surrounding Bay Area had grown exponentially in both its population and the number of cars that trafficked the area. The need for a bridge to connect San Francisco to Alameda County was acknowledged and authorized by an act of the California Legislature in 1929.

Engineering specifications and federal and state financing were being addressed by 1931, with final plans for a double-span suspension bridge approved and construction beginning on July 8, 1933. The bridge was opened to the public on November 12, 1936. Over 8000 workers were needed over the course of the project at a cost of $77 million (equivalent to $1.74 billion in 2024).

The Bay Bridge is an engineering marvel. With San Francisco Bay being up to 100 feet deep, new foundation laying techniques had to be developed. It was the longest bridge of its kind at the time, with the cantilever section being the longest in the nation and third-longest anywhere. The tunnel on Yerba Buena Island is the largest diameter transportation bore tunnel in the world.

For an overview of the historical significance and the construction details of the San Francisco-Oakland Bay Bridge, simply click on the following YouTube link provided by the California State Archives, that showcases its collection of bridge development and construction histories: