San Francisco bay is spanned by five bridges: the Golden Gate Bridge (which was the largest suspension bridge ever built at the time of its construction), the [Richmod-San Rafael Bridge]?, the [San Fransisco-Oakland Bay Bridge]?, the [Hayward-San Mateo Bridge]? and the Dumbarton Bridge.
The southern part of the San Francisco Peninsula including the city of San Jose is known as the Silicon Valley for its high concentration of high-tech, semiconductor and computer-related industry.