The Louisiana Purchase Exposition, informally known as The Saint Louis World's Fair, was a World's Fair held in Saint Louis, Missouri in 1904 which celebrated the centennial of the Louisiana Purchase (delayed one year). It opened April 30, 1904, and closed December 1 the same year. The Fair Grounds covered 1,200 acres, the largest space of any fair, and it was probably the most grand of the old style Pre-World War I Fairs. There were over 1500 individual buildings, connected by some 75 miles of roads and walkways, and it was said to be impossible to give even a hurried glance at everything there in less than a week. Exhibits were staged by 62 foreign nations, the United States government, 43 of the American states, in addition to the numerous exhibits put on by many industries, cities, private organizations and corporations, theater troops, music schools, etc.

The Fair hosted the 1904 Summer Olympic Games and on July 23 Charles E. Menches invented the ice cream cone at the Expo (although there are examples of prior art in England in 1888 and New York City in 1896). The hot dog and hamburger are sometimes also believed to have been invented at The Fair. Ragtime music was popularly featured.

This Fair is referred to in the 1944 Judy Garland Movie "Meet Me In St. Louis".

Left to right, top to bottom: 1)Palace of Varied Industries; 2)Palace of Mines & Metallurgy; 3)Entrance to Creation Exhibit on the Pike; 4) View from Observation Wheel, showing exhibitions New York to the North Pole, Galveston Flood, and Palace of Transportation.

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