The site for both the 1939 and 1964 World's Fairs was Flushing Meadows Park in Flushing, Queens, N.Y. Extensive work was done before the 1939 Fair to convert the site from its previous existence as a giant ash heap to a suitable park, fairgrounds and exhibition site. Parks Commissioner Robert Moses, who was to play a large role in the 1964 World's Fair plans, was involved in ensuring that the community would get a usable park after the Fair was over.

Despite the Great Depression and instability in Europe, engineer Joseph F. Shagden and Edward F. Roosevelt, cousin to United States President Franklin D. Roosevelt, began to plan in 1935 for a 1939 World's Fair to take place in New York City, its purpose being to "celebrate the 150th anniversary of the inauguration of George Washington and the launching of the new American government under the Constitution." The 1939 theme, "Building the World of Tomorrow," had as its grand architectural symbols an immense white sphere called the Perisphere and a triangular obelisk called the Trylon. A special attraction called "Democracity," illustrating the delights of a city of the future, was also a highlight of the exhibition. The Fair ran from April 30, 1939, to October 31, 1939, and then from May 11, 1940, to October 27, 1940. Dozens of countries participated, building grand pavilions to present their cultures and traditions to all Fair attendees. In addition, scores of businesses presented exhibits showcasing new wares and products, including the American companies General Electric, Consolidated Edison, and the National Broadcasting Corporation. Masterpieces of Renaissance art were also shown in art exhibitions, while the popular "Town of Tomorrow" showed fifteen demonstration homes, each designed to appeal to a different taste.

Decades later, another World's Fair took place on the same site. Parks Commissioner Robert Moses became president of the New York World's Fair Corporation and was instrumental in the pre-planning phases and implementation of improvements to the site. Construction on Shea Stadium (then known as Flushing Meadow Park Municipal Stadium and later demolished in 2009) also began at this time. Moses's interest in the World's Fair site coincided with a decision from the same time period to decline to support construction of a new stadium for the Brooklyn Dodgers.

The 1964 World's Fair ran from April 22, 1964, to October 18, 1964, and then from April 21, 1965, to October 17, 1965. Its theme was "Man in a Shrinking Globe in an Expanding Universe," an idea that seemed appropriate in the newly arrived space age. The architectural symbol of this fair was the Unisphere, which can still be viewed on the former site today. As with the previous fair, country pavilions showcased their cultures and cuisines, and business and industry exhibits showed products and innovations.