Perhaps more spectacular than Democracity was where it was housed. The gigantic dome, as they more perceptive of you may have guessed, was the Perisphere, wherein Democracity was displayed.
Entering the Perisphere.The Trylon and Perisphere had to be the most incredible pieces of temporary architecture ever built. Constructed of a steel frame covered with gypsum board, the Trylon was a triangluar tower 700 feet tall and the Perisphere was a sphere 200 feet in diameter; that works out to 18 stories tall.
At first glance, they looked to be nothing more than titanic abstract sculptures with the sphere seemingly supported by a fountain. But coming closer you saw that you could enter the sphere by way of an escalator; the world's largest. Inside the Democracity exhibit took up the entire interior with the incredible expanse of the sphere acting as an immense movie screen. You joined the show already in progress, followed it until you caught up with where you came in, and exited via a sky bridge to the Trylon, where you descended to the ground on a heliocline ramp.
One of the eeriest things about the Perisphere was that sometimes it seemed to be alive. At night, the Voice of the Perisphere could be heard on the fair grounds. This was a strange, atonal music caused by a vibrating piano wire inside a wooden box and transmitting the sound over loudspeakers hidden in the fountains under the sphere.
Here you can see a cross section of the Perisphere. Bear in mind that this gives you no idea of the scale of the thing. Imagine an Imax the size of a skyscraper and you get somewhere near the effect.
And if you're musically minded, this is the music that looped during your visit to the Perisphere. And here's the man who composed it.