More than 66 years after its completion, the Golden Gate Bridge, once the world's longest and tallest suspension bridge, stands at the entrance of the San Francisco Bay as a beloved international icon. Hanging from two 746-foot-high towers, the bridge is suspended by two massive main cables that contain 80,000 miles of wire and measure one yard in diameter. In fact, the Golden Gate Bridge cables contain enough wire to encircle the earth three times.
To leap across the mouth of an ocean harbor, something never before accomplished, civil engineers planted one pier in the open sea, 1,100-feet from the shore. Construction crews braved biting cold, 70-mph gusts and dizzying heights to complete the bridge in only four years. The bridge combines engineering strength and beauty. It survived the 1989 Loma Prieta earthquake suffering no damage, and in 66 years the bridge has only been shut briefly (longest closure was 3 hours and 27 minutes) to traffic three times due to periods of high sustaining winds.
A $400 million seismic retrofit, which will allow the bridge to withstand a nearby earthquake that measures 8.3 on the Richter scale, began in August 1997. Today, the Golden Gate Bridge remains one of the world's most revered and photographed bridges. It was also designated by ASCE as a Monument of the Millennium and a National Historic Civil Engineering Landmark.
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