Mare Island Naval Shipyard, California

Mare Island was one of the most important Navy shipyards in the country, and is a diversely developed self-contained city. It opened in 1854, and during the height of WWII over 46,000 people worked here. It was closed in 1996, and the 5,500 acre peninsula, with nearly 1,000 buildings, is being redeveloped. The working waterfront area is the dominant feature of the site, where several drydocks, cranes, and large engineering and assembly buildings continue to be used by civilian companies and reserve military forces. Among the prominent specialized buildings on base is a high bay engineering structure for the assembly of submarine periscopes, as nuclear submarines were some of the many types of navy vessels built and repaired at Mare Island. Over 500 ships were built here, and around 2,000 ships were refurbished or overhauled. Clean-up of contamination and unexploded bombs in some of the industrial areas continues, with over 12,000 ordnance items unearthed so far (not including bullets). The upland magazine area is the first of these sites to be remediated, and it is now a golf course. The southern edge of the island along the shore was a weapons storage and logistics area associated with the Concord Naval Weapons Center. Clusters of weapons magazines sit idle now. In addition to the shipyards, housing, and ordnance storage areas, a weapons manufacturing facility operated for over 100 years. Many of the buildings have thick walls and tin roofs, to direct the blast upward in the event of an accident. An air raid siren tower remains in the center of the complex, and rows of concrete air raid shelter booths line some streets of the base. The Fat Man atomic bomb is said to have visited Mare Island, on its way to Japan. Weapons areas may someday become a park, depending on the amount of unremoved hazards. The western side of the island had munitions storage, firing ranges, and dumps for dredged material from the shipyards, pumped over the island in a pipeline.