Golden Gate International Exhibition (1939-1940)
The idea was to celebrate the openings of the 'Bay' (1936) and Golden Gate (1937) bridges with a World's Fair
FDR approved $3,000,000 in funds to help with the reclamation of land from the Yerba Buena Shoals.
Treasure Island was man-made just north of Yerba Buena Island
with the Bay Bridge crossing over Yerba Buena. Treasure Island Fair - article by Gail Shea
Artificial Treasure Island was mainly an extravagant celebration area.
And with the start of WWII the Navy moved onto the island.