his collection of online links is no longer being maintained. That said, I can suggest one place to start your research.
Chicago Historical Society History Files - Century of Progress: "A Century of Progress took place in a "golden age" of world's fairs. The grand total of attendance for the two years was 48,769,227. In our time of instant communication, their popularity is waning. Chicago pulled out of a bid to host a world's fair in 1992, which would have marked the 100th anniversary of The Columbian Exposition--all the more reason to reflect on the marvel that was A Century of Progress."
I maintain two other pages dedicated to world's fairs: the 1893 Chicago Columbian Exposition and the 1939-40 New York World's Fair.