The Trylon and Perisphere were two modernistic structures, together known as the "Theme Center," at the center of the New York World's Fair of 1939-1940. Connected to the 610-foot (190 m) spire-shaped Trylon by what was at the time the world's longest escalator, the Perisphere was a tremendous sphere, 180 feet in diameter. The sphere housed a diorama called "Democracity" which, in keeping with the fair's theme "The World of Tomorrow", depicted a utopian city-of-the-future.