Original rivet from the Golden Gate Bridge in San Francisco. Opened in May, 1937, the bridge was put together with more than 1.2 million hand installed rivets like this one during its construction which started in January, 1933. The shaft of each rivet measured 1" in diameter and the head 1.5". This rivet was removed and replaced during seismic retrofit of the bridge following the 1989 Loma Prieta earthquake. Phase one of the project began in 1997 and phase three is scheduled for completion in 2014.