In the middle of San Francisco Bay sits an island that did not even exist a century ago. Built from dredged sand and rock in the 1930s, Treasure Island was created as the dazzling home of the 1939 Golden Gate International Exposition — a glowing Art Deco “Magic City” meant to celebrate the Bay Bridge, the Golden Gate Bridge, and California’s future. But after the fair closed and World War II began, that dream was erased almost overnight.

In this episode, we uncover how Treasure Island transformed from a world’s fair wonder into a major U.S. Navy base tied to radioactive training, contaminated ships from Operation Crossroads, and decades of secrecy. From flying boats and Pacifica statues to nuclear cleanup and modern redevelopment, this is the remarkable hidden history of San Francisco’s Treasure Island. #TreasureIsland #SanFrancisco #hiddenhistory

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