World's Fairs are always intended to promote the city or area that is holding them. Many did so with great success – Chicago's White City, Portland's Lewis & Clark, Seattle's Alaska-Yukon-Pacific and San Francisco's own Panama Pacific are all great examples. The Golden Gate International Exposition had a lot of challenges not the least of which was the lingering Great Depression and the 1939 New York World's Fair held simultaneously. It would not have happened without the support of the Federal Works Progress Administration.
Treasure Island, the site of the exposition, was originally a shipping hazard called the Yerba Buena Shoals. The 400 acre island was constructed by the WPA with a rock rim quarried from Yerba Buena Island to which it's attached. The interior was filled with topsoil over a base of dredged sand. WPA then topped it with the many buildings of the fair as plus two hangars and a building intended to be the Pan AM terminal of the airport for transpacific flying boats that would replace the fair at its end.
The GGIE celebrated the completion of the Bay Area's two major bridges, the San Francisco-Oakland Bay Bridge (1936) and the Golden Gate Bridge (1937). Its theme, Pageant of the Pacific, neatly avoided conflict with New York by focusing on the goods of nations bordering the Pacific. The exposition was open from February to October in 1939 and from May to September in 1940. While the theme was represented with an 80' statue called Pacifica, the most notable building was the 400' tall Tower of the Sun.
GGIE Tour Video
The Post Office issued stamps for both the GGIE and the New York World's Fair.