Octagonal Gold 50-Dollars, 1915S, San Francisco, head of Minerva left, rev owl on California pine branch, E PLURIBUS UNUM to right (F 189; KM 139)Only 483 struck. In 1915 visitors from all over the world converged on a veritable new city that had been built of lath and plaster on the San Francisco shore front. Building upon the tradition established by the 1876 Centennial Exhibition (Philadelphia), 1892-1893 World’s Columbian Exposition (Chicago), the 1900 Paris Exposition, the 1904 St. Louis World’s Fair, and other such events, the Panama-Pacific International Exposition showcased marvels of technology, art, history, and science. After the event ended, nearly everything was torn down. An exception was the Palace of Fine Arts, which, while never intended to be a permanent structure, survived to be used to store fire engines and other municipal equipment. In recent times it has been restored.