The Century of Progress was a world's fair held in Chicago, Illinois from 1933-1934 to celebrate Chicago's centennial. The theme of the fair was technological innovation.

The Century of Progress opened on May 27, 1933 on the shores of Lake Michigan on a 427 acre (1.7 km²) plot of land, much of which was landfill. Originally, the fair was scheduled only to run until November 12, but it was so successful that it was opened again to run from May 26 to October 31 the following year.

The fair was financed through sales of memberships, which allowed purchases of a certain number of admissions once the park was open. This was done so the fair would not have to be subsidized by the government. More than $800,000 was raised in this manner as the country came out of the Great Depression. A $10 million bond was issued on October 28, 1929, the day before the stock market crashed. By the time the fair closed in 1933, half of these notes had been retired, with all retired by the time the fair closed in 1934. In its two years, it had attracted 48,769,227 visitors.

The fair buildings were multi-colored, to create a "Rainbow City" as opposed to the "White City" of the World Columbian Exposition. The buildings generally had a linear Art Deco design to them in contrast to the Grecian aspect of the earlier fair.

One of the more famous aspects of the fair were the performances of fan dancer Sally Rand. Other popular exhibits were the various auto manufacturers, the Midway, and a recreation of important scenes from Chicago's history. The fair also contained exhibits that would seem shocking to contemporary audiences, including offensive portrayals of African-Americans, a "Midget Village" complete with "sixty Lilliputians", and an exhibition of incubators containing real babies.

Although the site of the fair is now home to the closed Meigs Field and McCormick Place, a column from the ruins of a Roman temple in Ostia given to Chicago by the Italian government to honor General Italo Balbo's 1933 trans-Atlantic flight still stands, although it has been moved to Soldier Field.