The Century 21 Exposition was a World's fair in Seattle, Washington in 1962.

The fair was deliberately planned to leave behind a fairground and numerous public buildings and public works; some credit it with revitalizing Seattle's economic and cultural life (see History of Seattle since 1940). The fair saw the construction of the Space Needle and Alweg Monorail, as well as several sports venues and performing arts buildings (most of which have since either been replaced or heavily remodeled since that time). The site (slightly expanded since the fair) is now called called Seattle Center; the United States Pavilion is now the Pacific Science Center. Another notable building in Seattle Center, the Experience Music Project, made a deliberate attempt to fit in with the fairground atmosphere, but actually dates from nearly 40 years later.

President John F. Kennedy was supposed to attend the closing ceremony of the fair on October 21, 1962. He bowed out, pleading a "cold". We now know that, in fact, he was dealing with the Cuban Missile Crisis.[1]