World's Fairs, also known as International Expositions, are large-scale exhibitions that highlight technology, agriculture, and other innovations of national or cultural significance. These fairs are open to the general public and can run for three weeks to six months.

The Century 21 Exposition, also known as the Seattle World's Fair, ran from April 21 to October 21, 1962. It began as an effort by Seattle city councilman Al Rochester (1895-1989) to revitalize the downtown core and recreate the success of the city's Alaska-Yukon-Pacific Exposition of 1909. It evolved within a few years under the direction of general manager Ewen Dingwall (1914-1996). He changed the initial "Festival of the West" theme to "America's Space Age World's Fair" after the 1957 launch of the Soviet Union's Sputnik satellite. The fair drew nearly 10 million attendees; unlike many other World's Fairs, it made a profit. It was also a cultural event that featured live telecasts on the Ed Sullivan Show, literary panels with Ray Bradbury (1920-2012) and Rod Serling (1924-1975), performances by Benny Goodman (1909-1986) and Count Basie (1904-1984), a visit from Elvis Presley (1935-1977) as he filmed the movie It Happened at the World's Fair (1963), and much more. The primary architect was Paul Thiry (1904-1993), who tapped numerous Seattle architecture firms, including the noted John Graham & Co., Minoru Yaasaki (1912-1986), and Lawrence Halprin (1916-2009) to complete the designs and execute the vision.