Golden Gate celebrates 75th with help of engineers

In this photo taken Wednesday, April, 18, 2012, a sign marking its 75th anniversary is shown near the Golden Gate Bridge in San Francisco. 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)