Found two major expositions held in the US beginning of 20th century, both celebrating the opening of the Panama Canal:
1) The Panama–California Exposition was an exposition held in San Diego, California, between January 1, 1915, and January 1, 1917,
2) The Panama–Pacific International Exposition was a world's fair held in San Francisco, California, United States, from February 20 to December 4, 1915
Is that picture taken at one of the two events?