In the early 1900's, settlers of the San Francisco Bay Area considered the San Francisco-Oakland Bay Bridge, which spans over eight miles long and 500 feet above the water at its highest point, an impossible feat. However, with only a few complications, the bridge was completed by November, 1936. The San Francisco-Oakland Bay Bridge consists of two bridge types. The east section is a cantilever bridge, and the west, a suspension bridge.

The 1.78 mile western span of the bridge between San Francisco and Yerba Buena Island presented the first obstacle. The bay was up to 100 feet deep in some places and required a new foundation-laying technique. Engineers developed a type of foundation called a pneumatic caisson to support the western section. A series of concrete cylinders were grouped together and then capped-off, having the air pressure of each cylinder identical to balance the beginning of the structure. From there, the...