Symbolism, Imagery, Allegory
If you've ever seen the musical Meet Me In Saint Louis, you know just what a big, fat, deal going to the World's Fair was. (Hint: a big enough deal that they made a Judy Garland musical about going to the World's Fair.)
Officially known at the World's Columbian Exposition, the Chicago World's Fair boasts all sorts of things to see and do. It's like Vegas, Disneyland, and Universal Studios rolled into one.
Though intended to celebrate human achievement, the fair is also meant to beat the French, who startled everyone with their 1889 Exposition Universelle (complete with the Eiffel Tower).
The Chicago fair lasts for only six months, but it records 27.5 million visits…and that's at a time when the nation's total population was 65 million. It occupies over one square mile and fills more than two hundred buildings. So yeah: it's pretty massive, bringing all sorts of people together, some who had never even been to a major city before.
The fair also shows that a city could be quite beautiful and idyllic…which was not what most people thought about cities at the turn of the 20th century:
The exposition revealed to its early visitors a vision of what a city could be and ought to be. (3.4.1)
And the White City—which is the nickname bestowed on the World's Fair—is especially beautiful compared to the Black City—the nickname of sooty, smelly Chicago—to the north. It offers a glimpse of everything American cities were striving to be: clean and bright. Upon arrival, visitors wore their best clothes and most somber expressions. It's like they had just entered an immense cathedral.
Olmsted wants the fair to produce an aura of "mysterious poetic effect" (2.1.19) and hoped the fair would have a theatrical effect on visitors. It certainly does, as the fair continues to impress right up until its final light show.