Louisiana Purchase Exposition Opens in St. Louis April 30, 1904
In 1904, St. Louis hosted a World's Fair to celebrate the centennial of the 1803 Louisiana Purchase. It was delayed from a planned opening in 1903 to 1904, to allow for full-scale participation by more states and foreign countries. The Fair opened April 30, 1904, and closed December 1, 1904. Of notable interest is that St. Louis had held an annual St. Louis Exposition since the 1880s as agricultural, trade, and scientific exhibitions, but this event was not held in 1904, due to the World's Fair.
The Fair's 1,200 acre (4.9 km²) site, designed by George Kessler,[1] was located at the present-day grounds of Forest Park and on the campus of Washington University, and was the largest fair to date. There were over 1,500 buildings, connected by some 75 miles (120 km) of roads and walkways. It was said to be impossible to give even a hurried glance at everything in less than a week. The Palace of Agriculture alone covered some 20 acres (324,000 m²).
Exhibits were staged by 62 foreign nations, the United States government, and 43 of the then-45 U.S. states. These featured industries, cities, private organizations and corporations, theater troupes, and music schools. There were also over 50 concession-type amusements found on "The Pike"; they provided educational and scientific displays, exhibits and imaginary 'travel' to distant lands, history and local boosterism (including Louis Wollbrinck's "Old St. Louis" and pure entertainment.
19,694,855 individuals were in attendance at the fair
http://en.wikipedia.org/wiki/Louisiana_Purchase_Exposition