Military biplanes fly between the towers of the Golden Gate Bridge as pedestrians walk across the span during opening ceremonies in San Francisco on May 27, 1937. (AP Photo)

Ed Stanley drives the golden rivet to mark the completion of the $35,000,000 Golden Gate Bridge spanning the entrance to San Francisco Bay, Ca., April 29, 1937. Holding the rivet is Ed Murphy and leaning over them is Joseph B. Strauss, chief engineer of the project. The bridge will be opened to the public May 27. (AP Photo)

Workmen assist the derrick operator, chief engineer Joseph Strauss, in joining the center of the Golden Gate Bridge in San Francisco, Ca., Nov. 18, 1936. The bridge has a main span of 4,200 feet, 1,280 meters, making it the world's longest suspension structure. (AP Photo)

This is a close up of one of the nearly completed cables which will hold up the floor of the $32,500,000 Golden Gate Bridge in San Francisco, Ca., May 4, 1936. Approximately 27,500 steel wires are in each cable, which are 36 1/2 inches in diameter and 7,700 feet long. The bridge spans the entrance to San Francisco harbor and joins the city with Marin County. (AP Photo)

Workers complete the catwalks for the Golden Gate Bridge, spanning the Golden Gate Strait, prior to spinning the bridge cables during construction in San Francisco, Ca., Oct. 25, 1935. (AP Photo)

Workers at the top of the tower, which will support the $35,000,000 suspension bridge, are shown during construction of one of the catwalks for the Golden Gate Bridge in San Francisco, Ca., Oct. 17, 1935. Below in background is the Marin County shore, which will be connected to San Francisco by the bridge. (AP Photo)

Workmen wearing steel helmets lay the catwalks for the Golden Gate Bridge in San Francisco, Ca., Sept. 19, 1935. Spinning of the big suspension cables will start after the two catwalks are laid high above the Golden Gate Strait. (AP Photo)

Workers install the first section of a huge safety net, at a cost of $98,000, that will extend from shore to shore beneath the Golden Gate Bridge span during construction of the bridge in San Francisco, Ca., Sept. 2, 1935. (AP Photo)

U.S. Secretary of Labor Frances Perkins, center, wears a steel helmet during an inspection tour of the San Francisco tower of the Golden Gate Bridge, Ca., March 25, 1935. Perkins, who is the first female cabinet officer in American history, talks with G.A. McClain, bridge superintendent, left, and S.E. Stanley, rivet foreman. (AP Photo)