The Unisphere was built and presented by the United States Steel Corporation to the 1964 World's Fair on April 22, 1964. It is made of stainless steel, stands 140 feet high, is 120 feet in diameter and weighs 350 tons. An inscription at the base states that it was, "Dedicated to man's aspirations toward Peace through mutual understanding and symbolizing his achievements in an expanding universe."
The Unisphere was built on the same site as the 18-story Perisphere, which along with the Trylon (a 700-foot tall triangular tower) was the iconic image of the 1939 fair. The Perisphere was a white sphere surrounded by clusters of fountains that gave it the appearance of being suspended on jets of water. The Perisphere contained a revolving platform from which visitors could view the "World of Tomorrow". However, even as the fair progressed, the world of tomorrow slowly became a world at war and the subsequent post-war suburbanization of America would bear no resemblence to Norman Bel Geddes sleek, streamlined vision of the city of the future.