The Century 21 Exposition, the first world's fair in the United States since World War II, opened in Seattle.

The Century 21 Exposition was a world's fair held April 21, 1962, to October 21, 1962, in Seattle, Washington, United States. Nearly 10 million people attended the fair during its six-month run.

A world's fair, also known as a universal exhibition, is a large global exhibition designed to showcase the achievements of nations. These exhibitions vary in character and are held in different parts of the world at a specific site for a period of time, typically between three and six months.

Seattle is the most populous city in the U.S. state of Washington and the Pacific Northwest region of North America. It is the 18th-most populous city in the United States with a population of 780,995 in 2024, while the Seattle metropolitan area at over 4.15 million residents is the 15th-most populous metropolitan area in the nation. The city is the county seat of King County, the most populous county in Washington. Seattle's growth rate of 21.1% between 2010 and 2020 made it one of the country's fastest-growing large cities.