The San Francisco-Oakland Bay Bridge (commonly known as the Bay Bridge) spans the San Francisco Bay. It consists of two spans, a the western suspension span shown in this picture and an eastern cantilever span. Like so much of the infrastructure in the U.S. the bridge was constructed during the great depression of the 1930s opening in 1936 six months before the Golden Gate Bridge. This is a time of renewal for the Bay Bridge – eastern section is being totally rebuild and the western section had its seismic retrofit.