Golden Gate celebrates 75th with help of engineers

In this photo taken Wednesday April 25, 2012, Golden Gate Bridge chief engineer Ewa Bauer talks about the extensive seismic retrofit progam at the Vista Point on the north side of the bridge in Sausalito, Calif. The bridge was heralded as an engineering marvel when it opened in 1937. It was the world's longest suspension span and had been built across a strait that critics said was too treacherous to be bridged. But as the iconic span approaches its 75th anniversary, the engineers who have overseen it all these years say keeping it up and open has been a feat unto itself. (AP Photo/Eric Risberg)