Caption: "San Francisco, Oakland Bay Bridge. Opening Day, Nov. 12, 1936." View of a portion of the ceremonies officially opening the San Francisco-Oakland Bay Bridge to traffic upon its completion in November 1936. The Bay Bridge's design combined three different types of bridge-building technology over the five miles it covers between San Francisco and Oakland: a suspension span, a cantilevered span, and a tunnel. At the time of its completion the bridge was the longest steel structure on the globe. It also featured the deepest bridge pier ever built, and the world's largest bore tunnel.