World's fairs and the smaller expositions which mimicked them were held in the late nineteenth and early twentieth centuries. The 1915 Panama-Pacific International Exposition (P.P.I.E.) celebrated the opening of the Panama Canal and celebrated the rebirth of its host city, San Francisco, after the devastating 1906 earthquake and fires. San Diego held a smaller fair, the Panama-California Exposition, the same year. San Francisco continued the world's fair tradition in 1939 with the Golden Gate International Exposition (G.G.I.E.), built on the man-made Treasure Island in the middle of the San Francisco Bay. Unlike the earlier world's fairs which usually employed classical motifs, the G.G.I.E. buildings were an interesting mix of modernism and Aztec and Mayan motifs.

Alaska Yukon Pacific Exposition, Seattle, (1909)

John Galen Howard

Golden Gate International Exposition, San Francisco, (1939)

Gardner Dailey
Katherine D. Jones
Bernard Maybeck
Francis J. McCarthy
William G. Merchant
William G. Merchant/Hans Gerson
Irving and Gertrude Morrow
Geraldine Knight Scott
Harry Shepherd
William Wurster

Panama-California International Exposition, Balboa Park, San Diego, (1915)

Paul Thiene

Panama-Pacific International Exposition, San Francisco, (1914-1915)

Bakewell and Brown
Katherine D. Jones
Bernard Maybeck
William G. Merchant/Hans Gerson
Louis Christian Mullgardt
Willis Polk

San Francisco Midwinter Fair, (1894)

Willis Polk